Merge pull request #12 from Twest2/StepForge pr/08-linux-apt-deb

Add production .deb packaging, apt setup, desktop integration, and icons (plan PR 8)

README.md

@@ -73,7 +73,12 @@ using only Node built-ins.
 
 For a Windows installation, see [docs/windows_installation](docs/windows_installation.md) or for a developer/more in depth walkthrough, see [docs/GETTING_STARTED.md](docs/GETTING_STARTED.md).
 
-On **Linux** (⚠️ work in progress — X11 vs Wayland, enabling per-click capture, the screen-share prompt), see [docs/GETTING_STARTED_WITH_LINUX.md](docs/GETTING_STARTED_WITH_LINUX.md).
+On **Linux**, install from a package built for your distro family:
+apt-based (Debian/Ubuntu) → [docs/linux/apt.md](docs/linux/apt.md); dnf-based
+(Fedora) → [docs/linux/dnf.md](docs/linux/dnf.md). Wayland uses the XDG portal
+for screen capture and a hotkey/interval trigger (per-click capture with a
+marker needs X11 + xinput). The general developer walkthrough is
+[docs/GETTING_STARTED_WITH_LINUX.md](docs/GETTING_STARTED_WITH_LINUX.md).
 
 Requirements: Node.js 22.12+ and npm (pinned in `.nvmrc`; installs are
 refused on older Nodes because the packaging toolchain needs 22.12+).

app/capture.js

@@ -198,11 +198,18 @@ class CaptureService {
     notify,
     screenApi = screen,
     textIntel = null,
+    powerPolicy = null,
   }) {
     this.store = store;
     this.settings = settings;
     this.getWindow = getWindow;
     this.notify = notify;
+    // Single owner of OS power/throttling state for the capture lifecycle.
+    // setRecording(true) is called exactly while a session is actively
+    // recording (session present and not paused); setRecording(false) whenever
+    // it pauses or ends. No-op by default so tests and non-Electron hosts work.
+    this.powerPolicy = powerPolicy || { setRecording() {} };
+    this._recordingPower = false;
     // Injectable for tests; the click/coordinate paths must never reach for
     // the global `screen` directly so coordinate handling stays testable.
     this.screen = screenApi;
@@ -213,6 +220,10 @@ class CaptureService {
     this.session = null; // { guideId, paused, count, intervalSec }
     this.intervalTimer = null;
     this.clickWatcher = null;
+    // Explicit trigger source rather than a bare boolean, so the UI can tell
+    // the truth about how clicks are being captured (or that they are not):
+    //   windows-hook | x11 | evdev-x11 | evdev-wayland | unavailable
+    this.clickSource = 'unavailable';
     this.frameLoopTimer = null;
     this.frameLoopRunning = false;
     this.frameWaiters = [];
@@ -240,6 +251,22 @@ class CaptureService {
     this.warmingUp = false;
   }
 
+  /**
+   * Reconcile OS power state with the actual recording state. Called after
+   * every session transition so there is exactly one owner: the blocker is
+   * held iff a session exists and is not paused. Idempotent.
+   */
+  syncPower() {
+    const recording = Boolean(this.session && !this.session.paused);
+    if (recording === this._recordingPower) return;
+    this._recordingPower = recording;
+    try {
+      this.powerPolicy.setRecording(recording);
+    } catch {
+      // power management is best-effort; never break capture over it
+    }
+  }
+
   state() {
     return this.session
       ? {
@@ -248,12 +275,21 @@ class CaptureService {
         guideId: this.session.guideId,
         count: this.session.count,
         intervalSec: this.session.intervalSec || 0,
-        clickCapture: Boolean(this.clickWatcher),
+        // clickCapture reflects any live global click source (xinput/evdev/
+        // Windows hook), not just the spawned-process watcher — evdev has no
+        // child process, so the old Boolean(this.clickWatcher) reported false
+        // while clicks were in fact being captured.
+        clickCapture: this.clickSource !== 'unavailable',
+        clickSource: this.clickSource,
         clickCaptureAvailable: this.clickCaptureAvailable(),
         clickFrameSource: this.streamBackend ? 'stream' : (this.frameLoopRunning ? 'loop' : 'idle'),
         strictClickFrames: this.strictClickFrames(),
       }
-      : { active: false, clickCaptureAvailable: this.clickCaptureAvailable() };
+      : {
+        active: false,
+        clickSource: this.clickSource,
+        clickCaptureAvailable: this.clickCaptureAvailable(),
+      };
   }
 
   /**
@@ -331,6 +367,9 @@ class CaptureService {
     this.session = { guideId, paused: true, count: 0, intervalSec: interval };
     if (this.settings.get('capture.captureOutsideClicks') !== false) this.startClickWatcher();
     this.applyInterval();
+    // A new session starts paused, so it must NOT hold the power blocker yet
+    // (it did before, leaking the blocker while idle). syncPower reconciles.
+    this.syncPower();
     this.notify('capture:state', this.state());
 
     // (Skipped for the dev screenshot hook, which needs a visible page.)
@@ -476,6 +515,9 @@ class CaptureService {
       this.stopFrameLoop();
       this.stopClickFrameBackend();
     }
+    // Recording only while unpaused: this is the one place tray/second-instance
+    // pauses previously bypassed, leaking the power blocker. syncPower owns it.
+    this.syncPower();
     if (this.rebuildTrayMenu) this.rebuildTrayMenu();
     this.notify('capture:state', this.state());
   }
@@ -555,6 +597,9 @@ class CaptureService {
     this.stopClickFrameBackend();
     this.destroySessionTray();
     this.session = null;
+    // A finished session never records: release the power blocker here so it
+    // can't outlive the recording (finish from any path — bar, tray, quit).
+    this.syncPower();
     if (this.hiddenForSession) {
       this.hiddenForSession = false;
       this.showWindow();
@@ -562,6 +607,23 @@ class CaptureService {
     this.notify('capture:state', this.state());
   }
 
+  /**
+   * Best-effort drain of clicks still encoding in the queue, for application
+   * shutdown. Resolves when the queue settles or the deadline passes so quit
+   * is never blocked indefinitely. Clicks captured mid-session are pinned to
+   * their guide id and stored even after the session ends (see onOsClick).
+   */
+  async drainPendingClicks(timeoutMs = 2000) {
+    try {
+      await Promise.race([
+        this.clickQueue.catch(() => {}),
+        new Promise((resolve) => setTimeout(resolve, Math.max(0, timeoutMs))),
+      ]);
+    } catch {
+      // best effort
+    }
+  }
+
   /**
    * True when the user is interacting with StepForge itself. Deliberately
    * based on cursor position over the visible window, not isFocused():
@@ -624,11 +686,22 @@ class CaptureService {
         if (result.ok) this.noteStepAdded(result.step, trigger, guideId);
         return result;
       }
-      // No usable frame: fall through to a one-off fresh shot — but only
-      // while still recording. After a stop, a fresh shot would show
-      // whatever replaced the user's workflow on screen.
-      clog('click@', clickAt, 'no frame qualified — falling back to a fresh (post-click) shot');
       if (!sessionLive) return { ok: false, reason: 'session ended before the fallback shot' };
+      // No usable pre-click frame. In strict mode a fresh shot now would be a
+      // POST-click frame — exactly what strict mode promises never to store.
+      // Skip with a visible diagnostic instead of silently labeling a
+      // post-click fallback as strict. Non-strict mode keeps the legacy
+      // fresh-shot fallback below.
+      if (this.strictClickFrames()) {
+        clog('click@', clickAt, 'strict mode — no pre-click frame; skipping rather than storing a post-click shot');
+        this.notify('capture:diagnostic', {
+          kind: 'strict-click-skipped',
+          guideId,
+          reason: 'No pre-click frame was ready for this click. In strict timing mode StepForge skips the shot rather than capturing the screen after the click.',
+        });
+        return { ok: false, reason: 'strict mode: no pre-click frame available for this click' };
+      }
+      clog('click@', clickAt, 'no frame qualified — falling back to a fresh (post-click) shot');
     }
 
     // For non-click triggers (interval, hotkey, manual) pull the latest frame
@@ -1009,6 +1082,7 @@ class CaptureService {
           ? ['stdbuf', '-oL', 'xinput', 'test-xi2', '--root']
           : ['xinput', 'test-xi2', '--root'];
         this.clickWatcher = spawn(argv[0], argv.slice(1), { stdio: ['ignore', 'pipe', 'ignore'] });
+        this.clickSource = 'x11';
         this.clickWatcher.stdout.on('data', (chunk) => {
           this.ingestClickWatcherChunk(chunk.toString(), 'linux');
         });
@@ -1374,6 +1448,7 @@ public static class SFHook {
           stdio: ['ignore', 'pipe', 'pipe'],
           windowsHide: true,
         });
+        this.clickSource = 'windows-hook';
         this.clickWatcher.stdout.on('data', (chunk) => {
           this.ingestClickWatcherChunk(chunk.toString(), 'win32');
         });
@@ -1425,6 +1500,7 @@ public static class SFHook {
       this.clickWatcher = null;
     }
     this.stopEvdevWatcher();
+    this.clickSource = 'unavailable';
     this.clickWatcherBuf = '';
     this.linuxEvent = null;
     this.discardPendingRawClick();
@@ -1450,26 +1526,48 @@ public static class SFHook {
           buf = rest;
           for (const button of presses) this.onOsClick(Date.now(), null, button);
         });
-        // A device can disappear (unplugged); just drop that stream.
-        stream.on('error', () => {});
+        // A device can disappear (unplugged): drop that stream, and if it was
+        // the last live click source, fall back like any other watcher loss
+        // instead of silently going dark.
+        stream.on('error', () => this.handleEvdevStreamLoss(stream, 'device read error'));
+        stream.on('close', () => this.handleEvdevStreamLoss(stream, 'device closed'));
         this.evdevStreams.push(stream);
       } catch {
         // Node became unreadable between enumeration and open — skip it.
       }
     }
     if (!this.evdevStreams.length) {
-      console.error('[stepforge] no readable mouse input devices — add your user to the "input" group for per-click capture: sudo usermod -aG input "$USER" (then log out and back in)');
+      this.clickSource = 'unavailable';
+      console.error('[stepforge] no readable mouse input devices for per-click capture (see docs/linux for the least-privilege device-access setup)');
     } else {
+      // evdev carries no cursor position on Wayland (no marker); on X11 without
+      // xinput it is the click source but likewise has no root coordinates.
+      this.clickSource = this.onWayland() ? 'evdev-wayland' : 'evdev-x11';
       console.log(`[stepforge] per-click capture via evdev on ${this.evdevStreams.length} device(s)${this.onWayland() ? ' (Wayland: no click marker)' : ''}`);
     }
   }
 
+  /** One evdev device stream ended; drop it and fall back if none remain. */
+  handleEvdevStreamLoss(stream, reason) {
+    if (!this.evdevStreams) return; // already stopped deliberately
+    const idx = this.evdevStreams.indexOf(stream);
+    if (idx === -1) return;
+    this.evdevStreams.splice(idx, 1);
+    try { stream.destroy(); } catch { /* already gone */ }
+    if (this.evdevStreams.length === 0) {
+      this.evdevStreams = null;
+      this.clickSource = 'unavailable';
+      this.handleClickWatcherLoss(`evdev ${reason}`);
+    }
+  }
+
   stopEvdevWatcher() {
     if (!this.evdevStreams) return;
-    for (const stream of this.evdevStreams) {
+    const streams = this.evdevStreams;
+    this.evdevStreams = null; // clear first so close handlers no-op
+    for (const stream of streams) {
       try { stream.destroy(); } catch { /* already closed */ }
     }
-    this.evdevStreams = null;
   }
 
   /**
@@ -2007,13 +2105,43 @@ public static class SFHook {
     const cropped = image.crop(rect);
     const size = cropped.getSize();
     if (!size.width || !size.height) return { ok: false, reason: 'empty selection' };
-    const step = await this.storeFrameAsStep(guideId, 'region', {
+    // storeFrameAsStep already returns { ok, step }; return it directly so
+    // callers see result.step.stepId — not result.step.step.stepId, which is
+    // what wrapping it in another { ok, step } produced (region selection and
+    // region auto-documentation both read result.step.stepId).
+    return this.storeFrameAsStep(guideId, 'region', {
       image: cropped,
       size,
       display,
       cursor: null,
     }, null, null);
-    return { ok: true, step };
+  }
+
+  /**
+   * Convert an overlay selection (display px) into an image-space crop rect,
+   * clamped to the image bounds. Returns null for an empty/invalid rect.
+   */
+  overlayRectToImageRect(rect, display, imgSize) {
+    if (!rect || !imgSize) return null;
+    const { width: iw, height: ih } = imgSize;
+    if (!iw || !ih) return null;
+    const sx = iw / display.bounds.width;
+    const sy = ih / display.bounds.height;
+    const toNum = (v) => (Number.isFinite(v) ? v : 0);
+    let x = Math.round(toNum(rect.x) * sx);
+    let y = Math.round(toNum(rect.y) * sy);
+    let w = Math.round(toNum(rect.w) * sx);
+    let h = Math.round(toNum(rect.h) * sy);
+    // Normalize negative-size drags (drawn up/left).
+    if (w < 0) { x += w; w = -w; }
+    if (h < 0) { y += h; h = -h; }
+    // Clamp to the image so image.crop can never read out of bounds.
+    x = Math.min(Math.max(0, x), iw);
+    y = Math.min(Math.max(0, y), ih);
+    w = Math.min(w, iw - x);
+    h = Math.min(h, ih - y);
+    if (w <= 0 || h <= 0) return null;
+    return { x, y, width: w, height: h };
   }
 
   /** Fullscreen overlay window that resolves with a crop rect (image px). */
@@ -2038,31 +2166,28 @@ public static class SFHook {
       });
       // The overlay may only display region.html; deny navigation/popups.
       require('./security').installWindowSecurity(overlay, 'region');
+      const { ipcMain } = require('electron');
       let settled = false;
+      // Idempotent cleanup: remove the IPC listener and close the overlay
+      // exactly once, whether the user picked, cancelled, closed, or the page
+      // failed to load. Previously the listener was only removed on a pick, so
+      // cancelling/closing leaked it (and the captured overlay/image refs).
       const finish = (rect) => {
         if (settled) return;
         settled = true;
+        ipcMain.removeListener('region:picked', onPick);
         if (!overlay.isDestroyed()) overlay.close();
         resolve(rect);
       };
-      const { ipcMain } = require('electron');
       const onPick = (event, rect) => {
         if (event.sender !== overlay.webContents) return;
-        ipcMain.removeListener('region:picked', onPick);
         if (!rect) return finish(null);
-        const imgSize = image.getSize();
-        const sx = imgSize.width / display.bounds.width;
-        const sy = imgSize.height / display.bounds.height;
-        finish({
-          x: Math.round(rect.x * sx),
-          y: Math.round(rect.y * sy),
-          width: Math.round(rect.w * sx),
-          height: Math.round(rect.h * sy),
-        });
+        finish(this.overlayRectToImageRect(rect, display, image.getSize()));
       };
       ipcMain.on('region:picked', onPick);
       overlay.on('closed', () => finish(null));
-      overlay.loadFile(path.join(__dirname, 'renderer', 'region.html'));
+      overlay.webContents.on('did-fail-load', () => finish(null));
+      overlay.loadFile(path.join(__dirname, 'renderer', 'region.html')).catch(() => finish(null));
     });
   }
 }

app/main.js

@@ -3,6 +3,7 @@
 const path = require('node:path');
 const fs = require('node:fs');
 const os = require('node:os');
+const { pathToFileURL } = require('node:url');
 const {
   app, BrowserWindow, ipcMain, dialog, shell, nativeTheme, globalShortcut,
   clipboard, nativeImage, screen, powerSaveBlocker, session, desktopCapturer,
@@ -16,7 +17,7 @@ const { buildRenderAst } = require('../core/renderast');
 const { runExport, EXPORTERS } = require('../exporters');
 const { runExportInWorker } = require('./export-runner');
 const { exportGuideArchive, importGuideArchive, saveLinkedGuide } = require('../core/archive');
-const { createSnapshot, listSnapshots, restoreSnapshot } = require('../core/snapshots');
+const { createSnapshot, listSnapshots, restoreSnapshot, autoSnapshotIfDue } = require('../core/snapshots');
 const { readLock } = require('../core/locks');
 const CaptureService = require('./capture');
 const { TextIntelService } = require('./text-intel');
@@ -71,6 +72,9 @@ function reindex(guideId) {
   } catch {
     // index failures must never block saves
   }
+  // Automatic backup policy runs on the same save choke point. It is
+  // self-contained and never throws, so it can't affect the save either.
+  autoSnapshotIfDue(store, guideId, settings);
 }
 
 function orderedSteps(guideId) {
@@ -204,7 +208,12 @@ function createWindow() {
           // Second scenario, reproducing the "I clicked many times but only
           // got two screenshots" report: a fast burst of clicks immediately
           // followed by finishing the session, so most clicks are still
-          // queued (frames still encoding) when the stop lands.
+          // queued (frames still encoding) when the stop lands. This scenario
+          // tests the queue DRAIN, not strict timing — 30ms-apart clicks
+          // outpace the frame sampler, so run it in balanced mode where every
+          // queued click stores. (Strict-mode skip-vs-store is covered by the
+          // marker scenario above and by unit tests.)
+          settings.set('capture.strictClickFrames', false);
           const burstGuide = store.createGuide({ title: 'burst selftest' });
           capture.startSession(burstGuide.guideId, { intervalSec: 0 });
           capture.stopClickWatcher();
@@ -228,6 +237,7 @@ function createWindow() {
           const burstSteps = store.getGuide(burstGuide.guideId).stepsOrder.length;
           console.log('CLICK-SELFTEST burst:', burstSteps, 'of', burstCount,
             burstSteps === burstCount ? 'OK — no clicks dropped on finish' : 'FAIL — clicks lost');
+          settings.set('capture.strictClickFrames', true); // restore for later scenarios
 
           // Helper: wait until armRecording has finished warming (window
           // hidden, buffer primed) so an injected click counts as a real
@@ -514,7 +524,12 @@ function setupIpc() {
   });
   h('step:imagePath', ({ guideId, stepId, which }) => {
     const p = store.stepImagePath(guideId, stepId, which || 'working');
-    return p && fs.existsSync(p) ? `file://${p}?v=${fs.statSync(p).mtimeMs}` : null;
+    if (!p || !fs.existsSync(p)) return null;
+    // pathToFileURL correctly encodes spaces, #, %, drive letters, etc.; the
+    // mtime is a cache-buster so the renderer reloads after an edit.
+    const url = pathToFileURL(p);
+    url.searchParams.set('v', String(fs.statSync(p).mtimeMs));
+    return url.href;
   }, {
     validate: (a) => c.id(a.guideId) && c.id(a.stepId)
       && (a.which === undefined || a.which === null || c.oneOf(a.which, ['original', 'working'])),
@@ -651,43 +666,20 @@ function setupIpc() {
     }
     return result;
   }, { validate: (a) => c.id(a.guideId) });
-  let capturePowerBlocker = -1;
-  const startCapturePower = () => {
-    if (!powerSaveBlocker.isStarted(capturePowerBlocker)) {
-      capturePowerBlocker = powerSaveBlocker.start('prevent-app-suspension');
-    }
-  };
-  const stopCapturePower = () => {
-    if (powerSaveBlocker.isStarted(capturePowerBlocker)) {
-      powerSaveBlocker.stop(capturePowerBlocker);
-    }
-  };
-
-  // Opt every live Electron process (browser, GPU, the screen-capture utility,
-  // any renderers) out of EcoQoS for the duration of a recording. The hidden
-  // capture-worker renderer is created later, during warmup, so it opts itself
-  // out separately (see stream-backend.js); this covers the rest.
-  const keepCaptureProcessesResponsive = () => {
-    try {
-      keepProcessesResponsive(app.getAppMetrics().map((m) => m.pid));
-    } catch { /* metrics unavailable — best effort */ }
-  };
 
+  // Power/throttling state is owned entirely by the capture service's
+  // recording transitions (see createCapturePowerPolicy) so there is exactly
+  // one owner: it is held iff a session is actively recording, and paused,
+  // finished, tray, and second-instance transitions all release it correctly.
   h('capture:session', async ({ action, guideId, intervalSec }) => {
     if (action === 'start') {
       capture.startSession(guideId, { intervalSec: intervalSec ?? null });
-      startCapturePower();
-      keepCaptureProcessesResponsive();
     } else if (action === 'pause') {
       capture.togglePause(true);
-      stopCapturePower();
     } else if (action === 'resume') {
       capture.togglePause(false);
-      startCapturePower();
-      keepCaptureProcessesResponsive();
     } else if (action === 'finish') {
       capture.finishSession();
-      stopCapturePower();
     } else if (action === 'interval') {
       capture.setInterval(intervalSec);
     }
@@ -745,6 +737,13 @@ function setupIpc() {
     return guide;
   }, { validate: (a) => c.id(a.guideId) && c.fileName(a.name) });
 
+  // recovery status: corrupt files quarantined this session and search index
+  // health, so the UI can surface them instead of data silently vanishing.
+  h('recovery:status', () => ({
+    quarantined: store.getRecoveryReport(),
+    searchStatus: searchIndex.status,
+  }));
+
   // templates
   const validFormat = (v) => c.oneOf(v, FORMATS);
   h('templates:list', ({ format }) => templates.list(format),
@@ -854,7 +853,7 @@ function setupIpc() {
     });
     const result = runExport(format, ast, previewDir, options || {});
     producedFiles.add(result.file);
-    return { ok: true, file: result.file, fileUrl: `file://${result.file}` };
+    return { ok: true, file: result.file, fileUrl: pathToFileURL(result.file).href };
   }, {
     validate: (a) => c.id(a.guideId) && validFormat(a.format)
       && (a.options === undefined || security.isPlainArgs(a.options)),
@@ -900,6 +899,9 @@ function setupIpc() {
     dataDir: store.root,
     platform: process.platform,
   }));
+  // Platform capture-capability profile (session type, portal/PipeWire,
+  // xinput, click source, actionable messages) for the diagnostics UI.
+  h('platform:capabilities', () => require('./platform').detectCapabilities());
 }
 
 // ---- lifecycle --------------------------------------------------------------
@@ -927,6 +929,17 @@ if (!gotLock) {
     store = new GuideStore(dataDir);
     settings = new Settings(store.settingsDir);
     searchIndex = new SearchIndex(store.indexDir);
+    // Rebuild/reconcile the index against the library at startup so a missing,
+    // corrupt, or version-mismatched index recovers instead of silently
+    // returning nothing.
+    try {
+      const summary = searchIndex.reconcile(store);
+      if (summary.reindexed || summary.removed || summary.status !== 'ok') {
+        console.log(`[stepforge] search index reconciled: ${JSON.stringify(summary)}`);
+      }
+    } catch (err) {
+      console.error(`[stepforge] search reconcile failed: ${err && err.message}`);
+    }
     templates = new TemplateManager(store.templatesDir);
     textIntel = new TextIntelService({
       store,
@@ -967,12 +980,36 @@ if (!gotLock) {
       }
     };
 
+    // Single owner of OS power/throttling state for recording. The capture
+    // service calls setRecording(true/false) on every recording transition;
+    // this holds a power-save blocker and opts live Electron processes out of
+    // EcoQoS while recording, and releases the blocker when recording stops.
+    const capturePowerPolicy = (() => {
+      let blocker = -1;
+      const keepResponsive = () => {
+        try { keepProcessesResponsive(app.getAppMetrics().map((m) => m.pid)); } catch { /* best effort */ }
+      };
+      return {
+        setRecording(recording) {
+          if (recording) {
+            if (!powerSaveBlocker.isStarted(blocker)) {
+              blocker = powerSaveBlocker.start('prevent-app-suspension');
+            }
+            keepResponsive();
+          } else if (powerSaveBlocker.isStarted(blocker)) {
+            powerSaveBlocker.stop(blocker);
+          }
+        },
+      };
+    })();
+
     capture = new CaptureService({
       store,
       settings,
       getWindow: () => mainWindow,
       notify: captureNotify,
       textIntel,
+      powerPolicy: capturePowerPolicy,
     });
 
     // Deny-by-default permission policy. The only grant in the entire app is
@@ -1025,6 +1062,19 @@ if (!gotLock) {
     });
   });
 
+  // Drain clicks still encoding in the capture queue before the app exits, so
+  // a fast burst immediately before quit is not lost. Defer the quit exactly
+  // once with a bounded deadline, then let it proceed.
+  let quitDrained = false;
+  app.on('before-quit', (event) => {
+    if (quitDrained || !capture) return;
+    quitDrained = true;
+    event.preventDefault();
+    // Stop new clicks from being queued, then wait for the queue to settle.
+    capture.stopClickWatcher();
+    capture.drainPendingClicks(2000).finally(() => app.quit());
+  });
+
   app.on('will-quit', () => {
     globalShortcut.unregisterAll();
     if (capture) {

app/platform/darwin/window-context.js

@@ -0,0 +1,43 @@
+'use strict';
+
+const { execFileSync } = require('node:child_process');
+
+/**
+ * macOS WindowContextProvider using AppleScript / System Events. Extracted
+ * verbatim from text-intel.js. macOS is not a primary support target, but the
+ * adapter is kept so the shared code has no `process.platform` branch and the
+ * behavior is preserved where it exists. Never throws.
+ */
+function createDarwinWindowContextProvider() {
+  return {
+    async collect() {
+      const script = `
+      set appName to ""
+      set windowTitle to ""
+      tell application "System Events"
+        try
+          set frontApp to first application process whose frontmost is true
+          set appName to name of frontApp
+          try
+            set windowTitle to name of front window of frontApp
+          end try
+        end try
+      end tell
+      return appName & linefeed & windowTitle
+    `;
+      try {
+        const result = execFileSync('osascript', ['-e', script], {
+          encoding: 'utf8',
+          stdio: ['ignore', 'pipe', 'pipe'],
+          timeout: 1200,
+        }).trimEnd();
+        const [appName = '', windowTitle = ''] = result.split(/\r?\n/);
+        return { appName, windowTitle };
+      } catch {
+        return { appName: '', windowTitle: '' };
+      }
+    },
+  };
+}
+
+module.exports = { createDarwinWindowContextProvider };

app/platform/index.js

@@ -0,0 +1,66 @@
+'use strict';
+
+/**
+ * The single factory that selects a platform implementation. The rest of the
+ * app depends on the interfaces in ./interfaces.js and asks this module for a
+ * concrete adapter — it never branches on `process.platform` itself.
+ *
+ * As Linux runtime capture is implemented, its ClickSource / ScreenFrameSource
+ * adapters are added here; today this provides the WindowContextProvider for
+ * every platform and the Linux capability diagnostics.
+ */
+
+const { assertWindowContextProvider } = require('./interfaces');
+
+function detectPlatform(platform = process.platform) {
+  if (platform === 'win32') return 'windows';
+  if (platform === 'darwin') return 'darwin';
+  if (platform === 'linux') return 'linux';
+  return 'unsupported';
+}
+
+/**
+ * Build the WindowContextProvider for the current OS. `platform` is injectable
+ * so the selection logic is unit-testable off the target OS.
+ */
+function createWindowContextProvider({ platform = process.platform } = {}) {
+  const os = detectPlatform(platform);
+  let provider;
+  switch (os) {
+    case 'windows':
+      provider = require('./windows/window-context').createWindowsWindowContextProvider();
+      break;
+    case 'darwin':
+      provider = require('./darwin/window-context').createDarwinWindowContextProvider();
+      break;
+    case 'linux':
+      provider = require('./linux/window-context').createLinuxWindowContextProvider();
+      break;
+    default:
+      // Unsupported OS: a null-object provider so callers still work.
+      provider = { async collect() { return { appName: '', windowTitle: '' }; } };
+  }
+  return assertWindowContextProvider(provider);
+}
+
+/**
+ * Capability profile for the current OS (used by diagnostics UI). Only Linux
+ * has a rich profile today; other platforms report their OS and a capable
+ * baseline.
+ */
+function detectCapabilities({ platform = process.platform, env = process.env } = {}) {
+  const os = detectPlatform(platform);
+  if (os === 'linux') {
+    return require('./linux/diagnostics').detectLinuxCapabilities({ env });
+  }
+  return {
+    os,
+    sessionType: os,
+    isWayland: false,
+    clickCapture: os === 'windows' ? 'windows-hook' : os,
+    screenCapture: os,
+    messages: [],
+  };
+}
+
+module.exports = { detectPlatform, createWindowContextProvider, detectCapabilities };

app/platform/interfaces.js

@@ -0,0 +1,62 @@
+'use strict';
+
+/**
+ * Platform adapter interfaces (documentation + light runtime shape checks).
+ *
+ * The platform-neutral capture/text-intel code consumes these interfaces and
+ * never inspects `process.platform` itself. `app/platform/index.js` is the
+ * only module that selects a concrete implementation. New OS support is a new
+ * set of files under `app/platform/<os>/`, not more conditionals inside the
+ * shared code.
+ *
+ * ---------------------------------------------------------------------------
+ * WindowContextProvider
+ *   collect(osPoint?: {x,y}) -> Promise<{
+ *     appName, windowTitle,
+ *     elementLabel?, elementRole?, elementClass?, elementValue?
+ *   }>
+ *   Best-effort foreground window / clicked-element context. Never throws;
+ *   returns {} (or partial) when unavailable.
+ *
+ * ClickSource   (runtime capture — implemented incrementally per platform)
+ *   describe() -> { source, coordinates: boolean, keyboard: boolean }
+ *     source ∈ 'windows-hook' | 'x11' | 'evdev-x11' | 'evdev-wayland' |
+ *              'wayland-portal' | 'hotkey' | 'interval' | 'unavailable'
+ *
+ * PowerPolicy
+ *   setRecording(recording: boolean) -> void
+ *   Holds/releases OS power + throttling state for the recording lifecycle.
+ *
+ * PlatformCapabilities  (from index.detectCapabilities())
+ *   { os, sessionType, isWayland, hasXinput, canSandbox, ... }
+ * ---------------------------------------------------------------------------
+ */
+
+// Interface names, exported so adapters and tests can reference a single
+// source of truth for the contract identifiers.
+const INTERFACES = Object.freeze([
+  'WindowContextProvider',
+  'ClickSource',
+  'PowerPolicy',
+]);
+
+const CLICK_SOURCES = Object.freeze([
+  'windows-hook',
+  'x11',
+  'evdev-x11',
+  'evdev-wayland',
+  'wayland-portal',
+  'hotkey',
+  'interval',
+  'unavailable',
+]);
+
+/** Assert a value looks like a WindowContextProvider (has async collect()). */
+function assertWindowContextProvider(provider) {
+  if (!provider || typeof provider.collect !== 'function') {
+    throw new Error('platform: WindowContextProvider must implement collect()');
+  }
+  return provider;
+}
+
+module.exports = { INTERFACES, CLICK_SOURCES, assertWindowContextProvider };

app/platform/linux/diagnostics.js

@@ -0,0 +1,99 @@
+'use strict';
+
+const fs = require('node:fs');
+const { execFileSync } = require('node:child_process');
+
+/**
+ * Linux capture-capability diagnostics. Detects the session type, portal /
+ * PipeWire availability, xinput, readable input devices, and the sandbox
+ * situation, and turns them into an actionable capability profile the UI can
+ * show instead of console-only failures.
+ *
+ * Pure detection with injectable probes so it is unit-testable without a real
+ * desktop session.
+ */
+
+function defaultHasBinary(name) {
+  try {
+    execFileSync('which', [name], { stdio: 'pipe' });
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+function detectSessionType(env = process.env) {
+  const t = String(env.XDG_SESSION_TYPE || '').toLowerCase();
+  if (t === 'wayland' || t === 'x11') return t;
+  if (env.WAYLAND_DISPLAY) return 'wayland';
+  if (env.DISPLAY) return 'x11';
+  return 'unknown';
+}
+
+function detectLinuxCapabilities({
+  env = process.env,
+  hasBinary = defaultHasBinary,
+  existsSync = fs.existsSync,
+  readdirSync = fs.readdirSync,
+} = {}) {
+  const sessionType = detectSessionType(env);
+  const isWayland = sessionType === 'wayland';
+
+  // XDG Desktop Portal + PipeWire are how Wayland screen capture works.
+  const hasPortalBus = Boolean(env.DBUS_SESSION_BUS_ADDRESS);
+  let hasPipeWire = false;
+  try {
+    hasPipeWire = hasBinary('pipewire') || existsSync(`/run/user/${process.getuid ? process.getuid() : ''}/pipewire-0`);
+  } catch {
+    hasPipeWire = hasBinary('pipewire');
+  }
+
+  const hasXinput = hasBinary('xinput');
+  const hasXprop = hasBinary('xprop');
+
+  // Readable /dev/input event nodes gate the evdev click fallback.
+  let readableInputDevices = 0;
+  try {
+    for (const name of readdirSync('/dev/input')) {
+      if (!/^event\d+$/.test(name)) continue;
+      try { fs.accessSync(`/dev/input/${name}`, fs.constants.R_OK); readableInputDevices += 1; } catch { /* not readable */ }
+    }
+  } catch { /* /dev/input not present */ }
+
+  // Determine the click-capture profile for this session.
+  let clickCapture;
+  if (!isWayland && hasXinput) clickCapture = 'x11-xinput';
+  else if (readableInputDevices > 0) clickCapture = isWayland ? 'evdev-wayland' : 'evdev-x11';
+  else clickCapture = 'hotkey-or-interval-only';
+
+  const messages = [];
+  if (isWayland && !hasPipeWire) {
+    messages.push('Wayland screen capture needs PipeWire and the XDG Desktop Portal. Install pipewire and xdg-desktop-portal.');
+  }
+  if (isWayland && !hasPortalBus) {
+    messages.push('No D-Bus session bus detected; the screen-share portal cannot be reached.');
+  }
+  if (!isWayland && !hasXinput) {
+    messages.push('xinput not found: per-click capture with a marker is unavailable on X11 without it.');
+  }
+  if (clickCapture === 'hotkey-or-interval-only') {
+    messages.push('No global click source available. Recording falls back to a hotkey or interval trigger.');
+  }
+
+  return {
+    os: 'linux',
+    sessionType,
+    isWayland,
+    hasPortalBus,
+    hasPipeWire,
+    hasXinput,
+    hasXprop,
+    readableInputDevices,
+    clickCapture,
+    // Portal capture is the safe Wayland baseline; X11 can grab directly.
+    screenCapture: isWayland ? 'wayland-portal' : 'x11-direct',
+    messages,
+  };
+}
+
+module.exports = { detectLinuxCapabilities, detectSessionType };

app/platform/linux/window-context.js

@@ -0,0 +1,51 @@
+'use strict';
+
+const { execFileSync } = require('node:child_process');
+
+function hasBinary(name) {
+  try {
+    execFileSync('which', [name], { stdio: 'pipe' });
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * Linux (X11) WindowContextProvider using xprop on the active window. On
+ * Wayland xprop only sees XWayland clients, so context is best-effort; the
+ * portal-based capture path does not depend on it. Extracted verbatim from
+ * text-intel.js. Never throws.
+ */
+function createLinuxWindowContextProvider() {
+  return {
+    async collect() {
+      try {
+        if (!hasBinary('xprop')) return { appName: '', windowTitle: '' };
+        const active = execFileSync('xprop', ['-root', '_NET_ACTIVE_WINDOW'], {
+          encoding: 'utf8',
+          stdio: ['ignore', 'pipe', 'pipe'],
+          timeout: 1200,
+        });
+        const activeMatch = active.match(/window id # (0x[0-9a-fA-F]+)/);
+        if (!activeMatch) return { appName: '', windowTitle: '' };
+        const winId = activeMatch[1];
+        const details = execFileSync('xprop', ['-id', winId, '_NET_WM_NAME', 'WM_NAME', 'WM_CLASS'], {
+          encoding: 'utf8',
+          stdio: ['ignore', 'pipe', 'pipe'],
+          timeout: 1200,
+        });
+        const titleMatch = details.match(/(?:_NET_WM_NAME\(UTF8_STRING\)|WM_NAME\(STRING\)|WM_NAME\(UTF8_STRING\)) = "([^"]*)"/);
+        const classMatch = details.match(/WM_CLASS\(STRING\) = "([^"]*)"(?:, "([^"]*)")?/);
+        return {
+          appName: classMatch ? (classMatch[2] || classMatch[1] || '') : '',
+          windowTitle: titleMatch ? titleMatch[1] : '',
+        };
+      } catch {
+        return { appName: '', windowTitle: '' };
+      }
+    },
+  };
+}
+
+module.exports = { createLinuxWindowContextProvider, hasBinary };

app/platform/windows/window-context.js

@@ -0,0 +1,88 @@
+'use strict';
+
+const { execFile } = require('node:child_process');
+
+/**
+ * Windows WindowContextProvider. Reads the foreground window (Win32) and, when
+ * a click point is given, the UI Automation element under it. Best-effort:
+ * resolves {} on any failure. Extracted verbatim from text-intel.js so the
+ * shared code carries no `process.platform` branch.
+ */
+function createWindowsWindowContextProvider() {
+  return {
+    async collect(osPoint = null) {
+      const hasPoint = osPoint && Number.isFinite(osPoint.x) && Number.isFinite(osPoint.y);
+      const clickX = hasPoint ? Number(osPoint.x) : 0;
+      const clickY = hasPoint ? Number(osPoint.y) : 0;
+      const script = `
+      $clickX = ${clickX};
+      $clickY = ${clickY};
+      $elementLabel = '';
+      $elementRole = '';
+      $elementClass = '';
+      $elementProcessId = 0;
+      $elementValue = '';
+      if (${hasPoint ? '$true' : '$false'}) {
+        try {
+          Add-Type -AssemblyName UIAutomationClient,UIAutomationTypes,WindowsBase | Out-Null
+          $point = New-Object System.Windows.Point($clickX, $clickY);
+          $element = [System.Windows.Automation.AutomationElement]::FromPoint($point);
+          if ($element) {
+            $current = $element.Current;
+            $elementLabel = $current.Name;
+            $elementRole = $current.LocalizedControlType;
+            $elementClass = $current.ClassName;
+            $elementProcessId = $current.ProcessId;
+            try {
+              $valPattern = [System.Windows.Automation.ValuePattern]::Pattern;
+              if ($element.GetSupportedPatterns() -contains $valPattern) {
+                $elementValue = $element.GetCurrentPattern($valPattern).Current.Value;
+              }
+            } catch { }
+          }
+        } catch { }
+      }
+      Add-Type @"
+using System;
+using System.Runtime.InteropServices;
+using System.Text;
+public static class Win32 {
+  [DllImport("user32.dll")] public static extern IntPtr GetForegroundWindow();
+  [DllImport("user32.dll", CharSet = CharSet.Unicode)]
+  public static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int count);
+  [DllImport("user32.dll")] public static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint processId);
+}
+"@;
+      $hWnd = [Win32]::GetForegroundWindow();
+      $sb = New-Object System.Text.StringBuilder 512;
+      [void][Win32]::GetWindowText($hWnd, $sb, $sb.Capacity);
+      $pid = 0;
+      [void][Win32]::GetWindowThreadProcessId($hWnd, [ref]$pid);
+      $proc = Get-Process -Id $pid -ErrorAction SilentlyContinue | Select-Object -First 1;
+      $out = [ordered]@{
+        appName = if ($proc) { $proc.ProcessName } else { '' };
+        windowTitle = $sb.ToString();
+        elementLabel = $elementLabel;
+        elementRole = $elementRole;
+        elementClass = $elementClass;
+        elementValue = $elementValue;
+        elementProcessId = $elementProcessId;
+        pid = $pid;
+      };
+      $out | ConvertTo-Json -Compress;
+    `;
+      return new Promise((resolve) => {
+        execFile('powershell.exe', ['-NoProfile', '-NonInteractive', '-ExecutionPolicy', 'Bypass', '-Command', script], {
+          encoding: 'utf8',
+          timeout: 4000,
+          windowsHide: true,
+        }, (err, stdout) => {
+          if (err) { resolve({}); return; }
+          try { resolve(JSON.parse(stdout.trim() || '{}')); } catch { resolve({}); }
+        });
+      });
+    },
+  };
+}
+
+module.exports = { createWindowsWindowContextProvider };

app/preload.js

@@ -77,6 +77,9 @@ const api = {
     create: invoke('snapshots:create'),
     restore: invoke('snapshots:restore'),
   },
+  recovery: {
+    status: invoke('recovery:status'),
+  },
   templates: {
     list: invoke('templates:list'),
     load: invoke('templates:load'),
@@ -104,6 +107,7 @@ const api = {
   },
   app: {
     info: invoke('app:info'),
+    platformCapabilities: invoke('platform:capabilities'),
   },
 };
 

app/renderer/editor.js

@@ -124,6 +124,7 @@ class GuideEditor {
     this.currentZoom = 'fit';
     this.pendingSave = false;
     this.pendingGuideSave = false;
+    this.saveError = null;
     this.canvasHistory = [];
     this.canvasFuture = [];
     this.beforeCanvasSnapshot = null;
@@ -151,9 +152,14 @@ class GuideEditor {
 
   setActive(active) {
     this.active = Boolean(active);
-    // Leaving the editor cancels any in-flight AI request for this guide so a
-    // slow response can't resolve against a guide the user has closed.
     if (!this.active && this.guideId) {
+      // Leaving the editor: flush pending debounced saves so navigation can
+      // never drop the last edit (failures keep the dirty state and retry),
+      // and cancel any in-flight AI request for this guide so a slow response
+      // can't resolve against a guide the user has closed.
+      if (this.pendingSave || this.pendingGuideSave) {
+        this.saveAll().catch(() => {});
+      }
       api.ai.cancel({ guideId: this.guideId }).catch(() => {});
     }
   }
@@ -319,6 +325,7 @@ class GuideEditor {
       selectedAnnotationId: this.selectedAnnotationId,
       linked: Boolean(this.guide && this.guide.linkedSource),
       dirty: this.pendingSave || this.pendingGuideSave || this.descriptionDirty || this.titleDirty,
+      saveError: this.saveError || null,
       view: 'editor',
     };
   }
@@ -1424,8 +1431,22 @@ class GuideEditor {
 
   async flushStep(step = this.currentStep) {
     if (!step) return;
+    // Clear the dirty flag only AFTER a durable save. Clearing it first meant
+    // a rejected IPC save silently lost the unsaved state (and this runs from
+    // a debounce that does not handle rejections). Keep it dirty on failure,
+    // surface it, and retry on the next edit or explicit save.
+    let saved;
+    try {
+      saved = await api.step.save({ guideId: this.guideId, step });
+    } catch (err) {
+      this.pendingSave = true;
+      this.saveError = (err && err.message) || 'Save failed';
+      this.emitMeta();
+      this.onToast('Could not save this step — your changes are kept. Retrying…', { error: true });
+      return null;
+    }
     this.pendingSave = false;
-    const saved = await api.step.save({ guideId: this.guideId, step });
+    this.saveError = null;
     const committed = this.commitSavedStep(saved);
     if (this.selectedStepId === committed.stepId) {
       this.renderStepList();
@@ -1470,8 +1491,17 @@ class GuideEditor {
 
   async flushGuide() {
     if (!this.guide) return;
+    try {
+      await api.guide.save({ guide: this.guide });
+    } catch (err) {
+      this.pendingGuideSave = true;
+      this.saveError = (err && err.message) || 'Save failed';
+      this.emitMeta();
+      this.onToast('Could not save guide details — your changes are kept. Retrying…', { error: true });
+      return;
+    }
     this.pendingGuideSave = false;
-    await api.guide.save({ guide: this.guide });
+    this.saveError = null;
     this.emitMeta();
   }
 

app/text-intel.js

@@ -2,7 +2,6 @@
 
 const fs = require('node:fs');
 const path = require('node:path');
-const { execFileSync, execFile } = require('node:child_process');
 
 const {
   DEFAULT_CAPTURE_TITLES,
@@ -23,15 +22,6 @@ const OCR_CROP = {
   height: 220,
 };
 
-function hasBinary(name) {
-  try {
-    execFileSync('which', [name], { stdio: 'pipe' });
-    return true;
-  } catch {
-    return false;
-  }
-}
-
 function clamp(v, min, max) {
   return Math.min(max, Math.max(min, v));
 }
@@ -63,6 +53,7 @@ class TextIntelService {
     dataDir,
     fetchImpl = global.fetch,
     screenApi = null,
+    windowContextProvider = null,
   }) {
     this.store = store;
     this.settings = settings;
@@ -70,6 +61,10 @@ class TextIntelService {
     this.dataDir = dataDir;
     this.fetch = fetchImpl;
     this.screen = screenApi;
+    // OS-specific foreground-window/element detection is a platform adapter.
+    // This code no longer branches on process.platform; the factory selects it.
+    this.windowContext = windowContextProvider
+      || require('./platform').createWindowContextProvider();
     this.worker = null;
     this.workerPromise = null;
     this.workerQueue = Promise.resolve();
@@ -271,135 +266,13 @@ class TextIntelService {
 
   async collectForegroundWindowContext(osPoint = null) {
     try {
-      if (process.platform === 'win32') return this.collectWindowsWindowContext(osPoint);
-      if (process.platform === 'darwin') return this.collectMacWindowContext();
-      if (process.platform === 'linux') return this.collectLinuxWindowContext();
+      return await this.windowContext.collect(osPoint);
     } catch {
       // best effort only
+      return { appName: '', windowTitle: '' };
     }
-    return { appName: '', windowTitle: '' };
   }
 
-  async collectWindowsWindowContext(osPoint = null) {
-    const hasPoint = osPoint && Number.isFinite(osPoint.x) && Number.isFinite(osPoint.y);
-    const clickX = hasPoint ? Number(osPoint.x) : 0;
-    const clickY = hasPoint ? Number(osPoint.y) : 0;
-    const script = `
-      $clickX = ${clickX};
-      $clickY = ${clickY};
-      $elementLabel = '';
-      $elementRole = '';
-      $elementClass = '';
-      $elementProcessId = 0;
-      $elementValue = '';
-      if (${hasPoint ? '$true' : '$false'}) {
-        try {
-          Add-Type -AssemblyName UIAutomationClient,UIAutomationTypes,WindowsBase | Out-Null
-          $point = New-Object System.Windows.Point($clickX, $clickY);
-          $element = [System.Windows.Automation.AutomationElement]::FromPoint($point);
-          if ($element) {
-            $current = $element.Current;
-            $elementLabel = $current.Name;
-            $elementRole = $current.LocalizedControlType;
-            $elementClass = $current.ClassName;
-            $elementProcessId = $current.ProcessId;
-            try {
-              $valPattern = [System.Windows.Automation.ValuePattern]::Pattern;
-              if ($element.GetSupportedPatterns() -contains $valPattern) {
-                $elementValue = $element.GetCurrentPattern($valPattern).Current.Value;
-              }
-            } catch { }
-          }
-        } catch { }
-      }
-      Add-Type @"
-using System;
-using System.Runtime.InteropServices;
-using System.Text;
-public static class Win32 {
-  [DllImport("user32.dll")] public static extern IntPtr GetForegroundWindow();
-  [DllImport("user32.dll", CharSet = CharSet.Unicode)]
-  public static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int count);
-  [DllImport("user32.dll")] public static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint processId);
-}
-"@;
-      $hWnd = [Win32]::GetForegroundWindow();
-      $sb = New-Object System.Text.StringBuilder 512;
-      [void][Win32]::GetWindowText($hWnd, $sb, $sb.Capacity);
-      $pid = 0;
-      [void][Win32]::GetWindowThreadProcessId($hWnd, [ref]$pid);
-      $proc = Get-Process -Id $pid -ErrorAction SilentlyContinue | Select-Object -First 1;
-      $out = [ordered]@{
-        appName = if ($proc) { $proc.ProcessName } else { '' };
-        windowTitle = $sb.ToString();
-        elementLabel = $elementLabel;
-        elementRole = $elementRole;
-        elementClass = $elementClass;
-        elementValue = $elementValue;
-        elementProcessId = $elementProcessId;
-        pid = $pid;
-      };
-      $out | ConvertTo-Json -Compress;
-    `;
-    return new Promise(resolve => {
-      execFile('powershell.exe', ['-NoProfile', '-NonInteractive', '-ExecutionPolicy', 'Bypass', '-Command', script], {
-        encoding: 'utf8',
-        timeout: 4000,
-        windowsHide: true,
-      }, (err, stdout) => {
-        if (err) { resolve({}); return; }
-        try { resolve(JSON.parse(stdout.trim() || '{}')); }
-        catch { resolve({}); }
-      });
-    });
-  }
-
-  collectMacWindowContext() {
-    const script = `
-      set appName to ""
-      set windowTitle to ""
-      tell application "System Events"
-        try
-          set frontApp to first application process whose frontmost is true
-          set appName to name of frontApp
-          try
-            set windowTitle to name of front window of frontApp
-          end try
-        end try
-      end tell
-      return appName & linefeed & windowTitle
-    `;
-    const result = execFileSync('osascript', ['-e', script], {
-      encoding: 'utf8',
-      stdio: ['ignore', 'pipe', 'pipe'],
-      timeout: 1200,
-    }).trimEnd();
-    const [appName = '', windowTitle = ''] = result.split(/\r?\n/);
-    return { appName, windowTitle };
-  }
-
-  collectLinuxWindowContext() {
-    if (!hasBinary('xprop')) return { appName: '', windowTitle: '' };
-    const active = execFileSync('xprop', ['-root', '_NET_ACTIVE_WINDOW'], {
-      encoding: 'utf8',
-      stdio: ['ignore', 'pipe', 'pipe'],
-      timeout: 1200,
-    });
-    const activeMatch = active.match(/window id # (0x[0-9a-fA-F]+)/);
-    if (!activeMatch) return { appName: '', windowTitle: '' };
-    const winId = activeMatch[1];
-    const details = execFileSync('xprop', ['-id', winId, '_NET_WM_NAME', 'WM_NAME', 'WM_CLASS'], {
-      encoding: 'utf8',
-      stdio: ['ignore', 'pipe', 'pipe'],
-      timeout: 1200,
-    });
-    const titleMatch = details.match(/(?:_NET_WM_NAME\(UTF8_STRING\)|WM_NAME\(STRING\)|WM_NAME\(UTF8_STRING\)) = "([^"]*)"/);
-    const classMatch = details.match(/WM_CLASS\(STRING\) = "([^"]*)"(?:, "([^"]*)")?/);
-    return {
-      appName: classMatch ? (classMatch[2] || classMatch[1] || '') : '',
-      windowTitle: titleMatch ? titleMatch[1] : '',
-    };
-  }
 
   async buildCaptureTitle({ mode, frame, clickPos, clickMeta = null }) {
     const ctx = await this.buildCaptureContext({ mode, frame, clickPos, clickMeta });
@@ -624,6 +497,10 @@ public static class Win32 {
       if (!guide || !step) {
         return { ok: false, reason: 'Guide or step not found.' };
       }
+      // Snapshot the revision now: AI generation is slow, and the user may
+      // edit the step meanwhile. We save with this expectedRevision so a
+      // response built from stale data cannot overwrite a newer user edit.
+      const baseRevision = Number.isInteger(step.revision) ? step.revision : 0;
 
       const currentBlock = blockId
         ? [...(step.textBlocks || []), ...(step.codeBlocks || []), ...(step.tableBlocks || [])].find((b) => b.id === blockId) || null
@@ -716,8 +593,26 @@ public static class Win32 {
         guideId,
       });
       const patch = normalizeAiPatch(raw);
-      const updated = applyAiPatchToStep(step, patch, { target, blockId });
-      const saved = this.store.saveStep(guideId, updated);
+      // Re-read the step: while generation ran, a capture auto-doc or another
+      // background write may have advanced it. Apply the patch to the current
+      // step and save with the original expected revision so a user edit made
+      // during generation causes a conflict instead of a silent overwrite.
+      let currentStep = step;
+      try {
+        currentStep = this.store.getStep(guideId, stepId) || step;
+      } catch {
+        currentStep = step;
+      }
+      const updated = applyAiPatchToStep(currentStep, patch, { target, blockId });
+      let saved;
+      try {
+        saved = this.store.saveStep(guideId, updated, { expectedRevision: baseRevision });
+      } catch (err) {
+        if (err && err.code === 'STEPFORGE_REVISION_CONFLICT') {
+          return { ok: false, reason: 'The step changed while AI was generating; nothing was overwritten.' };
+        }
+        throw err;
+      }
       return { ok: true, step: saved, patch };
     } catch (err) {
       return { ok: false, reason: err && err.message ? err.message : 'AI generation failed.' };

core/archive.js

@@ -124,18 +124,40 @@ function importGuideArchive(store, file, { mode = 'copy' } = {}) {
 }
 
 function finalizeImport(store, newGuide, idMap, stepJsons, stepFiles) {
+  // Transactional import: validate the guide and EVERY step first, then write
+  // the whole guide into a temporary staging directory, and only publish it
+  // with a single atomic rename. Previously guide.json was written before the
+  // steps validated, so a bad step left a partial guide in the library.
   validateGuide(newGuide);
-  writeJsonSync(path.join(store.guideDir(newGuide.guideId), 'guide.json'), newGuide);
-
+  const normalizedSteps = [];
   for (const [stepId, { raw }] of stepJsons) {
     const step = normalizeStep({ ...raw, stepId });
     step.parentStepId = raw.parentStepId ? idMap.get(raw.parentStepId) || null : null;
-    validateStep(step);
-    const dir = store.stepDir(newGuide.guideId, stepId);
-    writeJsonSync(path.join(dir, 'step.json'), step);
-    for (const { name, data } of stepFiles.get(stepId) || []) {
-      atomicWriteFileSync(path.join(dir, name), data);
+    validateStep(step); // throws before anything is written on a bad step
+    normalizedSteps.push([stepId, step]);
+  }
+
+  const finalDir = store.guideDir(newGuide.guideId);
+  if (fs.existsSync(finalDir)) throw new Error(`guide already exists: ${newGuide.guideId}`);
+  const stagingDir = `${finalDir}.importing-${Date.now()}`;
+  fs.rmSync(stagingDir, { recursive: true, force: true });
+  try {
+    fs.mkdirSync(stagingDir, { recursive: true });
+    writeJsonSync(path.join(stagingDir, 'guide.json'), newGuide);
+    for (const [stepId, step] of normalizedSteps) {
+      const dir = path.join(stagingDir, 'steps', stepId);
+      fs.mkdirSync(dir, { recursive: true });
+      writeJsonSync(path.join(dir, 'step.json'), step);
+      for (const { name, data } of stepFiles.get(stepId) || []) {
+        atomicWriteFileSync(path.join(dir, name), data);
+      }
     }
+    // Publish atomically. If the final dir appeared meanwhile, fail cleanly.
+    if (fs.existsSync(finalDir)) throw new Error(`guide already exists: ${newGuide.guideId}`);
+    fs.renameSync(stagingDir, finalDir);
+  } catch (err) {
+    fs.rmSync(stagingDir, { recursive: true, force: true });
+    throw err;
   }
   return store.getGuide(newGuide.guideId);
 }
@@ -160,7 +182,9 @@ function saveLinkedGuide(store, guideId, { force = false } = {}) {
     store.saveGuide(guide, { touch: false });
     return { saved: true, path: target };
   } finally {
-    releaseLock(target);
+    // Release by our acquisition token so we never remove a lock a concurrent
+    // force-steal replaced with theirs.
+    releaseLock(target, { lock: result.lock });
   }
 }
 

core/locks.js

@@ -20,18 +20,39 @@ function lockPathFor(archivePath) {
   return path.join(dir, `${stem}.lock-sfgz`);
 }
 
-function currentHolder() {
+function currentProcess() {
   return { host: os.hostname(), user: os.userInfo().username, pid: process.pid };
 }
 
+function currentHolder() {
+  return {
+    ...currentProcess(),
+    // Random per-acquisition token so two processes that happen to share
+    // host+user+pid space (containers, pid reuse) still compare distinctly,
+    // and so a steal can be detected by the previous holder.
+    token: `${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 10)}`,
+  };
+}
+
 function readLock(archivePath) {
   return readJsonIfExists(lockPathFor(archivePath), null);
 }
 
-function sameHolder(a, b) {
+// Process identity (host+user+pid). Used to decide whether an existing lock is
+// held by *this process* (safe to re-acquire) or someone else (a conflict).
+function sameProcess(a, b) {
   return a && b && a.host === b.host && a.user === b.user && a.pid === b.pid;
 }
 
+// Exact-acquisition identity via the per-acquisition token. Used by release so
+// a caller only removes the lock it actually took (never one a force-steal
+// replaced with its own).
+function sameAcquisition(existing, owner) {
+  if (!existing || !owner) return false;
+  if (owner.token) return existing.token === owner.token;
+  return sameProcess(existing, owner);
+}
+
 function isStale(lock, now = Date.now()) {
   const t = Date.parse(lock && lock.acquiredAt);
   return !Number.isFinite(t) || now - t > STALE_AFTER_MS;
@@ -44,24 +65,49 @@ function isStale(lock, now = Date.now()) {
  */
 function acquireLock(archivePath, { force = false } = {}) {
   const file = lockPathFor(archivePath);
-  const existing = readLock(archivePath);
   const me = currentHolder();
-  if (existing && !sameHolder(existing, me) && !isStale(existing) && !force) {
+  const lock = { ...me, acquiredAt: nowIso() };
+  const payload = JSON.stringify(lock, null, 2);
+
+  // Fast path: exclusive create. Only one writer wins the O_CREAT|O_EXCL race,
+  // so two processes can't both believe they hold the lock (the old
+  // read-then-write left exactly that window open).
+  try {
+    fs.writeFileSync(file, payload, { flag: 'wx' });
+    return { acquired: true, lock };
+  } catch (err) {
+    if (err.code !== 'EEXIST') throw err;
+  }
+
+  // A lock already exists. We may take it over only if this process already
+  // holds it, it is stale, or the caller is force-stealing (user confirmed).
+  const existing = readLock(archivePath);
+  if (existing && !sameProcess(existing, me) && !isStale(existing) && !force) {
     return { acquired: false, conflict: existing };
   }
-  const lock = { ...me, acquiredAt: nowIso() };
-  fs.writeFileSync(file, JSON.stringify(lock, null, 2));
+  // Overwrite to claim ownership (our token now identifies the lock).
+  fs.writeFileSync(file, payload);
   return { acquired: true, lock };
 }
 
-/** Release only if we are the holder (or force). */
-function releaseLock(archivePath, { force = false } = {}) {
+/**
+ * Release only if we are the holder (or force). Pass the `lock` (or its
+ * `token`) returned by acquireLock so ownership is matched by token — the
+ * per-acquisition token means a fresh currentHolder() would not match.
+ */
+function releaseLock(archivePath, { force = false, lock = null, token = null } = {}) {
   const file = lockPathFor(archivePath);
   const existing = readLock(archivePath);
   if (!existing) return true;
-  if (!force && !sameHolder(existing, currentHolder())) return false;
+  // With no explicit lock/token, fall back to process identity (the legacy
+  // "release my own lock" path) rather than a fresh token that can't match.
+  const owner = lock || (token ? { token } : currentProcess());
+  if (!force && !sameAcquisition(existing, owner)) return false;
   fs.rmSync(file, { force: true });
   return true;
 }
 
-module.exports = { lockPathFor, readLock, acquireLock, releaseLock, isStale, STALE_AFTER_MS };
+module.exports = {
+  lockPathFor, readLock, acquireLock, releaseLock, isStale, STALE_AFTER_MS,
+  sameProcess, sameAcquisition,
+};

core/schema.js

@@ -52,6 +52,9 @@ function createGuide(fields = {}) {
     favorite: Boolean(fields.favorite),
     linkedSource: fields.linkedSource || null,
     exportProfiles: { ...(fields.exportProfiles || {}) },
+    // Monotonic revision for optimistic concurrency. Absent in v1 data (reads
+    // as 0), bumped on every store write.
+    revision: Number.isInteger(fields.revision) && fields.revision >= 0 ? fields.revision : 0,
   };
 }
 
@@ -89,6 +92,8 @@ function createStep(fields = {}) {
     captureMetadata: (fields.captureMetadata && typeof fields.captureMetadata === 'object' && !Array.isArray(fields.captureMetadata))
       ? { ...fields.captureMetadata }
       : null,
+    // Monotonic revision for optimistic concurrency (see createGuide).
+    revision: Number.isInteger(fields.revision) && fields.revision >= 0 ? fields.revision : 0,
   };
 }
 

core/search.js

@@ -14,7 +14,7 @@ const { blockText } = require('./blocks');
  * specific step in the editor.
  */
 
-const INDEX_VERSION = 1;
+const INDEX_VERSION = 2;
 
 function tokenize(text) {
   if (!text) return [];
@@ -27,20 +27,82 @@ function tokenize(text) {
 class SearchIndex {
   constructor(indexDir) {
     this.file = path.join(indexDir, 'search-index.json');
+    // Per-guide source fingerprints so a startup reconcile can tell which
+    // guides changed while the app was closed, without re-reading every step.
+    this.fingerprints = {}; // guideId -> fingerprint string
+    // Recovery status surfaced to the UI: 'ok' | 'reset' (missing/corrupt/
+    // version mismatch) | 'reconciled' (rebuilt from the store at startup).
+    this.status = 'ok';
+    const fileExisted = require('node:fs').existsSync(this.file);
     const stored = readJsonIfExists(this.file, null);
-    if (stored && stored.version === INDEX_VERSION) {
+    if (stored && stored.version === INDEX_VERSION && stored.docs && typeof stored.docs === 'object') {
       this.docs = stored.docs;
+      this.fingerprints = stored.fingerprints || {};
     } else {
+      // Missing, corrupt, or an older index version: start empty and mark it,
+      // so reconcile() rebuilds from the store instead of silently staying
+      // blank (which made search "work" but return nothing). A file that
+      // existed but could not be used is a 'reset' (recovery-worthy); a
+      // genuinely absent index on first run is just 'ok'.
       this.docs = {}; // docKey -> { guideId, stepId, title, text, updatedAt }
+      this.status = fileExisted ? 'reset' : 'ok';
     }
   }
 
   persist() {
-    writeJsonSync(this.file, { version: INDEX_VERSION, docs: this.docs });
+    writeJsonSync(this.file, {
+      version: INDEX_VERSION,
+      docs: this.docs,
+      fingerprints: this.fingerprints,
+    });
+  }
+
+  static fingerprint(guide) {
+    return `${guide.updatedAt || ''}:${Number.isInteger(guide.revision) ? guide.revision : 0}`;
+  }
+
+  /**
+   * Reconcile the index against the store at startup: reindex guides that are
+   * new or changed (by fingerprint), and drop index entries for guides that no
+   * longer exist. Returns a summary with a recovery status for the UI.
+   */
+  reconcile(store) {
+    const guides = store.listGuides();
+    const liveIds = new Set(guides.map((g) => g.guideId));
+    let reindexed = 0;
+    let removed = 0;
+
+    // Drop docs/fingerprints for guides that are gone.
+    for (const key of Object.keys(this.fingerprints)) {
+      if (!liveIds.has(key)) {
+        this.removeGuide(key, { persist: false });
+        delete this.fingerprints[key];
+        removed += 1;
+      }
+    }
+
+    for (const guide of guides) {
+      const fp = SearchIndex.fingerprint(guide);
+      const indexed = this.fingerprints[guide.guideId];
+      const hasDoc = Boolean(this.docs[`g:${guide.guideId}`]);
+      if (indexed === fp && hasDoc) continue; // unchanged
+      try {
+        this.indexGuide(guide, store.listSteps(guide.guideId), { persist: false });
+        reindexed += 1;
+      } catch {
+        // A single unreadable guide must not abort the whole reconcile.
+      }
+    }
+
+    this.persist();
+    if (this.status === 'reset' || reindexed > 0 || removed > 0) {
+      this.status = this.status === 'reset' ? 'reset' : 'reconciled';
+    }
+    return { status: this.status, reindexed, removed, total: guides.length };
   }
 
   /** (Re)index one guide and all of its steps. */
-  indexGuide(guide, stepsMap) {
+  indexGuide(guide, stepsMap, { persist = true } = {}) {
     this.removeGuide(guide.guideId, { persist: false });
 
     const placeholderText = Object.entries(guide.placeholders || {})
@@ -69,13 +131,15 @@ class SearchIndex {
         updatedAt: guide.updatedAt,
       };
     }
-    this.persist();
+    this.fingerprints[guide.guideId] = SearchIndex.fingerprint(guide);
+    if (persist) this.persist();
   }
 
   removeGuide(guideId, { persist = true } = {}) {
     for (const key of Object.keys(this.docs)) {
       if (this.docs[key].guideId === guideId) delete this.docs[key];
     }
+    delete this.fingerprints[guideId];
     if (persist) this.persist();
   }
 

core/snapshots.js

@@ -3,7 +3,8 @@
 const fs = require('node:fs');
 const path = require('node:path');
 const { zipDirSync, extractZipSync } = require('./zip');
-const { atomicWriteFileSync } = require('./util');
+const { atomicWriteFileSync, readJsonSync } = require('./util');
+const { validateGuide } = require('./schema');
 
 /**
  * Snapshot backups: a zip of the guide directory (excluding history/) stored
@@ -16,7 +17,11 @@ function snapshotsDir(store, guideId) {
 }
 
 function snapshotName(label) {
-  const stamp = new Date().toISOString().replace(/[:.]/g, '-').replace(/-\d{3}Z$/, 'Z');
+  // Keep milliseconds: stripping them made two snapshots taken within the same
+  // second collide on filename (the second silently overwrote the first, so
+  // rapid automatic backups produced only one file). ms keeps names unique and
+  // still chronologically sortable.
+  const stamp = new Date().toISOString().replace(/[:.]/g, '-');
   return label ? `${stamp}-${label.replace(/[^A-Za-z0-9_-]+/g, '_')}.zip` : `${stamp}.zip`;
 }
 
@@ -50,20 +55,103 @@ function pruneSnapshots(store, guideId, keepLast) {
 /**
  * Restore a snapshot: replaces the guide's current content (guide.json and
  * steps/) with the snapshot's, keeping the history/ directory intact.
+ *
+ * The extraction is staged and validated BEFORE any live content is touched:
+ * a corrupt or truncated snapshot can no longer destroy the current guide.
+ * The swap itself moves the old content aside, moves the new content in, then
+ * deletes the old — so a failure mid-swap leaves a recoverable state.
  */
 function restoreSnapshot(store, guideId, name) {
   const file = path.join(snapshotsDir(store, guideId), path.basename(name));
   if (!fs.existsSync(file)) throw new Error(`snapshot not found: ${name}`);
   const buf = fs.readFileSync(file);
   const guideDir = store.guideDir(guideId);
-  // Safety: snapshot the pre-restore state too, so a restore is undoable.
-  createSnapshot(store, guideId, { label: 'pre-restore' });
-  for (const entry of fs.readdirSync(guideDir)) {
-    if (entry === 'history') continue;
-    fs.rmSync(path.join(guideDir, entry), { recursive: true, force: true });
+
+  // 1. Extract + validate into a temp staging dir. Nothing live is touched yet.
+  const staging = `${guideDir}.restoring-${Date.now()}`;
+  fs.rmSync(staging, { recursive: true, force: true });
+  try {
+    fs.mkdirSync(staging, { recursive: true });
+    extractZipSync(buf, staging);
+    const guideJson = path.join(staging, 'guide.json');
+    if (!fs.existsSync(guideJson)) throw new Error('snapshot is missing guide.json');
+    validateGuide(readJsonSync(guideJson)); // throws on a corrupt snapshot
+  } catch (err) {
+    fs.rmSync(staging, { recursive: true, force: true });
+    throw new Error(`snapshot restore aborted (snapshot invalid): ${err.message}`);
   }
-  extractZipSync(buf, guideDir);
+
+  // 2. Snapshot the pre-restore state so the restore is itself undoable.
+  createSnapshot(store, guideId, { label: 'pre-restore' });
+
+  // 3. Swap in the validated content, preserving history/. Move live content
+  //    aside first so we can roll back if a step fails.
+  const backup = `${guideDir}.prev-${Date.now()}`;
+  const liveEntries = fs.readdirSync(guideDir).filter((e) => e !== 'history');
+  fs.mkdirSync(backup, { recursive: true });
+  try {
+    for (const entry of liveEntries) {
+      fs.renameSync(path.join(guideDir, entry), path.join(backup, entry));
+    }
+    for (const entry of fs.readdirSync(staging)) {
+      if (entry === 'history') continue;
+      fs.renameSync(path.join(staging, entry), path.join(guideDir, entry));
+    }
+  } catch (err) {
+    // Roll back: restore whatever we moved aside.
+    for (const entry of fs.readdirSync(backup)) {
+      const dest = path.join(guideDir, entry);
+      fs.rmSync(dest, { recursive: true, force: true });
+      fs.renameSync(path.join(backup, entry), dest);
+    }
+    fs.rmSync(backup, { recursive: true, force: true });
+    fs.rmSync(staging, { recursive: true, force: true });
+    throw err;
+  }
+  fs.rmSync(backup, { recursive: true, force: true });
+  fs.rmSync(staging, { recursive: true, force: true });
   return store.getGuide(guideId);
 }
 
-module.exports = { createSnapshot, listSnapshots, pruneSnapshots, restoreSnapshot, snapshotsDir };
+/**
+ * Automatic backup policy. Every guide keeps a small save counter in its
+ * history dir; once `everyNSaves` saves accumulate (and backups.automatic is
+ * on) an automatic snapshot is taken and old ones pruned to backups.keepLast.
+ * Returns the snapshot name when one was taken, else null. Never throws — a
+ * backup failure must not break the save that triggered it.
+ */
+function autoSnapshotIfDue(store, guideId, settings) {
+  try {
+    const backups = (settings && settings.get && settings.get('backups')) || {};
+    if (backups.automatic === false) return null;
+    const everyN = Number.isInteger(backups.everyNSaves) && backups.everyNSaves > 0 ? backups.everyNSaves : 25;
+    const keepLast = Number.isInteger(backups.keepLast) && backups.keepLast > 0 ? backups.keepLast : 10;
+
+    const dir = path.join(store.guideDir(guideId), 'history');
+    fs.mkdirSync(dir, { recursive: true });
+    const counterFile = path.join(dir, 'autosave-counter.json');
+    let count = 0;
+    try {
+      count = JSON.parse(fs.readFileSync(counterFile, 'utf8')).count || 0;
+    } catch { count = 0; }
+    count += 1;
+
+    if (count >= everyN) {
+      createSnapshot(store, guideId, { label: 'auto', keepLast });
+      count = 0;
+      atomicWriteFileSync(counterFile, JSON.stringify({ count }));
+      return true;
+    }
+    atomicWriteFileSync(counterFile, JSON.stringify({ count }));
+    return null;
+  } catch (err) {
+    // Best effort: report, never break the caller's save.
+    console.error(`[stepforge] automatic backup failed for ${guideId}: ${err && err.message}`);
+    return null;
+  }
+}
+
+module.exports = {
+  createSnapshot, listSnapshots, pruneSnapshots, restoreSnapshot, snapshotsDir,
+  autoSnapshotIfDue,
+};

core/store.js

@@ -12,6 +12,22 @@ const {
 } = require('./schema');
 const { sanitizeHtml } = require('./sanitize');
 
+/**
+ * Thrown by revision-aware saves when the on-disk revision no longer matches
+ * the caller's expectation — i.e. someone else wrote in between. Callers that
+ * pass expectedRevision (background/AI/capture writes) use this to avoid
+ * clobbering a newer user edit.
+ */
+class RevisionConflictError extends Error {
+  constructor(kind, id, expected, actual) {
+    super(`${kind} ${id} changed since it was read (expected revision ${expected}, found ${actual})`);
+    this.name = 'RevisionConflictError';
+    this.code = 'STEPFORGE_REVISION_CONFLICT';
+    this.expected = expected;
+    this.actual = actual;
+  }
+}
+
 /**
  * Folder-based guide store. One directory per guide, one directory per step,
  * all JSON written atomically. This is the only module that knows the
@@ -27,21 +43,49 @@ class GuideStore {
     this.guidesDir = path.join(this.libraryDir, 'guides');
     this.indexDir = path.join(this.libraryDir, 'index');
     this.trashDir = path.join(this.libraryDir, 'trash');
+    this.quarantineDir = path.join(this.libraryDir, 'quarantine');
     this.tempDir = path.join(rootDir, 'temp');
     this.sharedLinksDir = path.join(rootDir, 'shared-links');
     this.foldersFile = path.join(this.libraryDir, 'folders.json');
+    // In-memory log of files quarantined this session (corrupt/unreadable),
+    // surfaced to the UI instead of silently vanishing.
+    this.recoveryReport = [];
     this.ensureLayout();
   }
 
   ensureLayout() {
     for (const dir of [
       this.settingsDir, this.templatesDir, this.guidesDir, this.indexDir,
-      this.trashDir, this.tempDir, this.sharedLinksDir,
+      this.trashDir, this.quarantineDir, this.tempDir, this.sharedLinksDir,
     ]) {
       fs.mkdirSync(dir, { recursive: true });
     }
   }
 
+  /**
+   * Move a corrupt/unreadable file or directory into quarantine (preserving
+   * the original bytes) and record it, rather than silently dropping it. A
+   * guide/step never just disappears without an explanation.
+   */
+  quarantine(sourcePath, kind, reason) {
+    const stamp = `${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
+    const dest = path.join(this.quarantineDir, `${kind}-${path.basename(sourcePath)}-${stamp}`);
+    try {
+      fs.mkdirSync(this.quarantineDir, { recursive: true });
+      fs.renameSync(sourcePath, dest);
+    } catch {
+      // If we cannot move it (e.g. cross-device or vanished), still record it.
+    }
+    const entry = { kind, source: sourcePath, quarantined: dest, reason: String(reason || 'unreadable'), at: nowIso() };
+    this.recoveryReport.push(entry);
+    return entry;
+  }
+
+  /** Corrupt files quarantined this session (for a recovery UI). */
+  getRecoveryReport() {
+    return [...this.recoveryReport];
+  }
+
   guideDir(guideId) {
     if (!/^[a-zA-Z0-9_-]+$/.test(guideId)) throw new Error(`bad guide id: ${guideId}`);
     return path.join(this.guidesDir, guideId);
@@ -70,10 +114,19 @@ class GuideStore {
     return normalizeGuide(raw);
   }
 
-  saveGuide(guide, { touch = true } = {}) {
+  saveGuide(guide, { touch = true, expectedRevision = null } = {}) {
     validateGuide(guide);
+    // Optimistic concurrency: a caller that read the guide can pass the
+    // revision it saw; if disk moved on since, refuse rather than clobber.
+    if (expectedRevision !== null) {
+      const current = this.guideExists(guide.guideId) ? this.getGuide(guide.guideId).revision : 0;
+      if (current !== expectedRevision) {
+        throw new RevisionConflictError('guide', guide.guideId, expectedRevision, current);
+      }
+    }
     const stored = deepClone(guide);
     stored.descriptionHtml = sanitizeHtml(stored.descriptionHtml);
+    stored.revision = (Number.isInteger(stored.revision) ? stored.revision : 0) + 1;
     if (touch) stored.updatedAt = nowIso();
     writeJsonSync(path.join(this.guideDir(guide.guideId), 'guide.json'), stored);
     return stored;
@@ -83,11 +136,16 @@ class GuideStore {
     const out = [];
     for (const entry of fs.readdirSync(this.guidesDir, { withFileTypes: true })) {
       if (!entry.isDirectory()) continue;
-      const file = path.join(this.guidesDir, entry.name, 'guide.json');
+      const dir = path.join(this.guidesDir, entry.name);
+      const file = path.join(dir, 'guide.json');
+      if (!fs.existsSync(file)) continue; // in-progress/empty dir, not corruption
       try {
         out.push(normalizeGuide(readJsonSync(file)));
-      } catch {
-        // skip unreadable entries rather than failing the whole library
+      } catch (err) {
+        // A corrupt guide.json used to make the guide silently vanish from the
+        // library. Quarantine the directory (preserving it) and record it so
+        // the user can be told, instead of losing it without explanation.
+        this.quarantine(dir, 'guide', err && err.message);
       }
     }
     out.sort((a, b) => (a.updatedAt < b.updatedAt ? 1 : -1));
@@ -211,18 +269,38 @@ class GuideStore {
     if (!fs.existsSync(stepsRoot)) return map;
     for (const entry of fs.readdirSync(stepsRoot, { withFileTypes: true })) {
       if (!entry.isDirectory()) continue;
+      const dir = path.join(stepsRoot, entry.name);
+      const file = path.join(dir, 'step.json');
+      if (!fs.existsSync(file)) continue;
       try {
-        map.set(entry.name, normalizeStep(readJsonSync(path.join(stepsRoot, entry.name, 'step.json'))));
-      } catch {
-        // skip unreadable step
+        map.set(entry.name, normalizeStep(readJsonSync(file)));
+      } catch (err) {
+        // Quarantine a corrupt step (preserving it) and record it rather than
+        // silently dropping it from the guide.
+        this.quarantine(dir, 'step', err && err.message);
       }
     }
     return map;
   }
 
-  saveStep(guideId, step) {
+  saveStep(guideId, step, { expectedRevision = null } = {}) {
+    // Optimistic concurrency for background/AI/capture writes: refuse to
+    // overwrite a step that changed since it was read. Direct user edits pass
+    // no expectedRevision (last-write-wins — the user is the authority).
+    if (expectedRevision !== null) {
+      let current = 0;
+      try {
+        current = this.getStep(guideId, step.stepId).revision;
+      } catch {
+        current = 0; // step vanished; treat as revision 0
+      }
+      if (current !== expectedRevision) {
+        throw new RevisionConflictError('step', step.stepId, expectedRevision, current);
+      }
+    }
     const stored = normalizeStep(deepClone(step));
     stored.descriptionHtml = sanitizeHtml(stored.descriptionHtml);
+    stored.revision = (Number.isInteger(stored.revision) ? stored.revision : 0) + 1;
     validateStep(stored);
     writeJsonSync(path.join(this.stepDir(guideId, step.stepId), 'step.json'), stored);
     const guide = this.getGuide(guideId);
@@ -352,4 +430,4 @@ class GuideStore {
   }
 }
 
-module.exports = { GuideStore };
+module.exports = { GuideStore, RevisionConflictError };

core/zip.js

@@ -121,8 +121,22 @@ function zipSync(entries, { date = new Date(2026, 0, 1) } = {}) {
   return Buffer.concat([...localParts, centralBuf, eocd]);
 }
 
-/** Parse a zip buffer into [{ name, data }] with CRC verification. */
-function unzipSync(buffer) {
+// Resource limits for untrusted archives (share files, snapshots). These cap
+// memory and disk work so a ZIP bomb can't exhaust the machine. Callers that
+// build archives themselves may relax them; imports use the defaults.
+const DEFAULT_UNZIP_LIMITS = {
+  maxEntries: 50000,
+  maxTotalCompressed: 1024 * 1024 * 1024, // 1 GiB of stored bytes
+  maxTotalUncompressed: 4 * 1024 * 1024 * 1024, // 4 GiB inflated total
+  maxEntryUncompressed: 512 * 1024 * 1024, // 512 MiB per entry
+};
+
+/**
+ * Parse a zip buffer into [{ name, data }] with CRC verification and hard
+ * resource limits. `limits` overrides DEFAULT_UNZIP_LIMITS.
+ */
+function unzipSync(buffer, { limits = {} } = {}) {
+  const lim = { ...DEFAULT_UNZIP_LIMITS, ...limits };
   if (!Buffer.isBuffer(buffer) || buffer.length < 22) throw new Error('zip: too small');
   // Find end-of-central-directory record (scan backwards over the comment).
   let eocd = -1;
@@ -132,11 +146,14 @@ function unzipSync(buffer) {
   }
   if (eocd < 0) throw new Error('zip: end record not found');
   const count = buffer.readUInt16LE(eocd + 10);
+  if (count > lim.maxEntries) throw new Error(`zip: too many entries (${count} > ${lim.maxEntries})`);
   let pos = buffer.readUInt32LE(eocd + 16);
 
   const entries = [];
+  let totalCompressed = 0;
+  let totalUncompressed = 0;
   for (let i = 0; i < count; i++) {
-    if (buffer.readUInt32LE(pos) !== 0x02014b50) throw new Error('zip: bad central header');
+    if (pos + 46 > buffer.length || buffer.readUInt32LE(pos) !== 0x02014b50) throw new Error('zip: bad central header');
     const method = buffer.readUInt16LE(pos + 10);
     const crc = buffer.readUInt32LE(pos + 16);
     const compSize = buffer.readUInt32LE(pos + 20);
@@ -151,17 +168,33 @@ function unzipSync(buffer) {
     assertSafeEntryName(name);
     if (name.endsWith('/')) continue; // directory entry
 
+    // Budget checks BEFORE allocating/inflating: the declared sizes are
+    // attacker-controlled, so reject oversize claims up front.
+    if (uncompSize > lim.maxEntryUncompressed) {
+      throw new Error(`zip: entry too large (${uncompSize} > ${lim.maxEntryUncompressed}): ${name}`);
+    }
+    totalCompressed += compSize;
+    totalUncompressed += uncompSize;
+    if (totalCompressed > lim.maxTotalCompressed) throw new Error('zip: total compressed size exceeds limit');
+    if (totalUncompressed > lim.maxTotalUncompressed) throw new Error('zip: total inflated size exceeds limit');
+
     if (buffer.readUInt32LE(localOffset) !== 0x04034b50) throw new Error('zip: bad local header');
     const lNameLen = buffer.readUInt16LE(localOffset + 26);
     const lExtraLen = buffer.readUInt16LE(localOffset + 28);
     const dataStart = localOffset + 30 + lNameLen + lExtraLen;
+    if (dataStart + compSize > buffer.length) throw new Error(`zip: entry data out of range: ${name}`);
     const raw = buffer.subarray(dataStart, dataStart + compSize);
 
     let data;
     if (method === 0) data = Buffer.from(raw);
-    else if (method === 8) data = zlib.inflateRawSync(raw);
-    else throw new Error(`zip: unsupported method ${method} for ${name}`);
+    else if (method === 8) {
+      // Cap inflation so a small deflate stream can't expand to gigabytes —
+      // even if the declared uncompSize lied, this is the real guard.
+      data = zlib.inflateRawSync(raw, { maxOutputLength: lim.maxEntryUncompressed });
+    } else throw new Error(`zip: unsupported method ${method} for ${name}`);
 
+    // Exact length match (not "at least"): the inflated bytes must equal the
+    // declared uncompressed size, and the CRC must verify.
     if (data.length !== uncompSize) throw new Error(`zip: size mismatch for ${name}`);
     if (crc32(data) !== crc) throw new Error(`zip: CRC mismatch for ${name}`);
     entries.push({ name, data });
@@ -170,10 +203,10 @@ function unzipSync(buffer) {
 }
 
 /** Extract a zip buffer under destDir; every path is traversal-checked. */
-function extractZipSync(buffer, destDir) {
+function extractZipSync(buffer, destDir, { limits = {} } = {}) {
   const resolvedDest = path.resolve(destDir);
   const written = [];
-  for (const { name, data } of unzipSync(buffer)) {
+  for (const { name, data } of unzipSync(buffer, { limits })) {
     const target = path.resolve(resolvedDest, name);
     if (target !== resolvedDest && !target.startsWith(resolvedDest + path.sep)) {
       throw new Error(`zip: entry escapes destination: ${name}`);
@@ -203,4 +236,7 @@ function zipDirSync(dir, { filter = () => true, prefix = '' } = {}) {
   return zipSync(entries);
 }
 
-module.exports = { crc32, zipSync, unzipSync, extractZipSync, zipDirSync, assertSafeEntryName };
+module.exports = {
+  crc32, zipSync, unzipSync, extractZipSync, zipDirSync, assertSafeEntryName,
+  DEFAULT_UNZIP_LIMITS,
+};

docs/linux/apt.md

@@ -0,0 +1,67 @@
+# StepForge on apt-based Linux (Debian / Ubuntu)
+
+This is the setup and packaging guide for **apt-based** distributions. Fedora
+and other dnf-based systems have a separate guide: [dnf.md](dnf.md).
+
+## Install from the .deb
+
+```bash
+sudo apt install ./stepforge_<version>_amd64.deb
+```
+
+apt pulls the required runtime libraries automatically (they are declared as
+`Depends`). The package installs:
+
+- the app and a fixed Electron runtime under `/opt/stepforge`,
+- the `stepforge` launcher at `/usr/bin/stepforge`,
+- a desktop entry, icons, and `.sfgz`/`.sfglt` file associations.
+
+Launch it from your application menu or run `stepforge`.
+
+### Sandbox
+
+The launcher runs **sandboxed**. On most modern kernels the Chromium
+user-namespace sandbox works out of the box; the package's `postinst` also
+makes the setuid `chrome-sandbox` helper usable as a fallback. StepForge will
+**not** silently launch unsandboxed — see the launcher's message if the
+sandbox is unavailable.
+
+## Install from the portable tarball
+
+```bash
+tar -xzf stepforge_<version>_linux-x64.tar.gz
+# Install the runtime libraries first (see below), then run:
+./usr/bin/stepforge         # or move opt/stepforge to /opt and use the launcher
+```
+
+The tarball includes the `/usr/bin/stepforge` launcher (unlike older builds).
+Install the runtime libraries with:
+
+```bash
+bash scripts/linux/apt/install-runtime-deps.sh
+```
+
+## Capture capabilities on apt systems
+
+- **X11**: full per-click capture with an accurate marker (needs `xinput`).
+- **Wayland**: screen capture via the XDG Desktop Portal + PipeWire; the
+  portal asks permission once per recording. Per-click capture with
+  coordinates is not exposed by Wayland, so recording uses a global hotkey or
+  interval trigger. StepForge reports the active trigger honestly.
+
+Run StepForge and open Settings → Diagnostics to see the detected session
+type, portal/PipeWire status, and the active capture profile.
+
+## Build the .deb yourself
+
+```bash
+bash scripts/linux/apt/install-build-deps.sh   # dpkg-dev, fakeroot, xvfb, …
+nvm install && nvm use                          # pinned Node 22 (see .nvmrc)
+npm ci
+npm run package:linux:deb                        # -> build/artifacts/*.deb + tarball + sha256
+```
+
+The builder stages **only** runtime files: the app code, a fixed Electron
+runtime, and production npm dependencies. It never copies the development
+`node_modules`, docs, prompts, or examples, and it fails if `node_modules` is
+missing rather than producing an unusable artifact.

package.json

@@ -14,7 +14,10 @@
     "start": "node scripts/start-electron.js",
     "test": "node scripts/run-unit-tests.js",
     "sample": "node scripts/make-sample-guide.js",
+    "icons": "node scripts/make-icons.js",
     "package:windows": "node scripts/package-windows.js",
+    "package:linux:deb": "bash packaging/linux/debian/package.sh",
+    "package:linux:rpm": "bash packaging/linux/fedora/package.sh",
     "build": "bash scripts/build-release.sh",
     "verify": "bash scripts/verify.sh",
     "bootstrap": "bash scripts/bootstrap-offline.sh"

packaging/assets/stepforge.svg

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  StepForge application icon — original artwork.
+  A rising staircase of three blocks (the "steps" of a step-by-step guide)
+  over a rounded square, in the app's blue. No third-party assets.
+-->
+<svg xmlns="http://www.w3.org/2000/svg" width="256" height="256" viewBox="0 0 256 256">
+  <defs>
+    <linearGradient id="bg" x1="0" y1="0" x2="0" y2="1">
+      <stop offset="0" stop-color="#2563eb"/>
+      <stop offset="1" stop-color="#1e3a8a"/>
+    </linearGradient>
+  </defs>
+  <rect x="0" y="0" width="256" height="256" rx="56" fill="url(#bg)"/>
+  <!-- Three ascending steps -->
+  <g fill="#ffffff">
+    <rect x="52"  y="150" width="52" height="54" rx="8"/>
+    <rect x="102" y="116" width="52" height="88" rx="8"/>
+    <rect x="152" y="82"  width="52" height="122" rx="8"/>
+  </g>
+  <!-- Capture spark on the top step -->
+  <circle cx="178" cy="60" r="16" fill="#facc15"/>
+</svg>

packaging/linux/common/launcher.sh

@@ -0,0 +1,71 @@
+#!/usr/bin/env sh
+# StepForge launcher installed at /usr/bin/stepforge.
+#
+# Runs the packaged Electron runtime against the installed app at
+# /opt/stepforge. It NEVER installs or repairs anything at runtime and it does
+# NOT silently disable the Chromium sandbox: an unsandboxed launch requires the
+# explicit STEPFORGE_ALLOW_NO_SANDBOX=1 opt-in (development/CI only).
+
+set -eu
+
+APP_DIR=/opt/stepforge
+ELECTRON="$APP_DIR/node_modules/electron/dist/electron"
+SANDBOX_HELPER="$APP_DIR/node_modules/electron/dist/chrome-sandbox"
+
+if [ ! -x "$ELECTRON" ]; then
+  echo "stepforge: Electron runtime missing at $ELECTRON (reinstall the package)." >&2
+  exit 1
+fi
+
+cd "$APP_DIR" || exit 1
+
+# Linux screen capture: enable the PipeWire path for Wayland portals; harmless
+# on X11 where Ozone auto-selects.
+COMMON_ARGS="--enable-features=WebRTCPipeWireCapturer --ozone-platform-hint=auto"
+
+sandbox_ok() {
+  [ -e "$SANDBOX_HELPER" ] || return 1
+  helper_uid="$(stat -c '%u' "$SANDBOX_HELPER" 2>/dev/null || echo '')"
+  helper_mode="$(stat -c '%a' "$SANDBOX_HELPER" 2>/dev/null || echo '')"
+  [ "$helper_uid" = "0" ] || return 1
+  [ -n "$helper_mode" ] || return 1
+  # setuid bit set?
+  [ $(( $((8#$helper_mode)) & 04000 )) -ne 0 ] || return 1
+  return 0
+}
+
+userns_ok() {
+  # Namespaced sandbox works without the setuid helper on kernels that allow
+  # unprivileged user namespaces.
+  if [ -r /proc/sys/kernel/unprivileged_userns_clone ]; then
+    [ "$(cat /proc/sys/kernel/unprivileged_userns_clone)" = "1" ] && return 0 || return 1
+  fi
+  if [ -r /proc/sys/kernel/apparmor_restrict_unprivileged_userns ]; then
+    [ "$(cat /proc/sys/kernel/apparmor_restrict_unprivileged_userns)" = "0" ] && return 0 || return 1
+  fi
+  [ -e /proc/self/ns/user ] && return 0 || return 1
+}
+
+if sandbox_ok || userns_ok; then
+  exec "$ELECTRON" $COMMON_ARGS "$APP_DIR" "$@"
+fi
+
+if [ "${STEPFORGE_ALLOW_NO_SANDBOX:-}" = "1" ] || [ "${ELECTRON_DISABLE_SANDBOX:-}" = "1" ]; then
+  echo "stepforge: launching WITHOUT the Chromium sandbox (explicit opt-in)." >&2
+  exec "$ELECTRON" --no-sandbox $COMMON_ARGS "$APP_DIR" "$@"
+fi
+
+cat >&2 <<'MSG'
+stepforge: the Chromium sandbox is not available and StepForge will not launch
+unsandboxed by default.
+
+Fix one of the following:
+  * Make the setuid sandbox helper usable:
+      sudo chown root:root /opt/stepforge/node_modules/electron/dist/chrome-sandbox
+      sudo chmod 4755 /opt/stepforge/node_modules/electron/dist/chrome-sandbox
+  * Enable unprivileged user namespaces (kernel/sysctl dependent):
+      sudo sysctl -w kernel.unprivileged_userns_clone=1
+
+For development/CI only you may set STEPFORGE_ALLOW_NO_SANDBOX=1 to override.
+MSG
+exit 1

packaging/linux/common/stepforge-mime.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
+  <mime-type type="application/x-stepforge-guide">
+    <comment>StepForge guide archive</comment>
+    <glob pattern="*.sfgz"/>
+    <icon name="stepforge"/>
+  </mime-type>
+  <mime-type type="application/x-stepforge-template">
+    <comment>StepForge export template</comment>
+    <glob pattern="*.sfglt"/>
+    <icon name="stepforge"/>
+  </mime-type>
+</mime-info>

packaging/linux/common/stepforge.desktop

@@ -0,0 +1,13 @@
+[Desktop Entry]
+Type=Application
+Name=StepForge
+GenericName=Step-by-step guide capture
+Comment=Capture, annotate, and export step-by-step guides
+Exec=stepforge %U
+Icon=stepforge
+Terminal=false
+Categories=Office;Graphics;Utility;
+Keywords=documentation;screenshot;guide;capture;steps;
+StartupNotify=true
+StartupWMClass=StepForge
+MimeType=application/x-stepforge-guide;

packaging/linux/debian/control.in

@@ -0,0 +1,17 @@
+Package: stepforge
+Version: @VERSION@
+Section: utils
+Priority: optional
+Architecture: @ARCH@
+Depends: libnss3, libnspr4, libatk1.0-0, libatk-bridge2.0-0, libcups2, libgbm1, libasound2, libgtk-3-0, libxkbcommon0, libatspi2.0-0
+Recommends: xinput, x11-utils, xdg-desktop-portal, pipewire
+Maintainer: @MAINTAINER@
+Homepage: https://github.com/Twest2/StepForge
+Description: Local-first step-by-step guide capture and export tool
+ StepForge captures step-by-step workflows as screenshots, lets you annotate
+ and describe each step, and exports to Markdown, PDF, DOCX, PPTX, HTML, and
+ more. Local-first: no telemetry, with an optional user-configured local AI
+ integration.
+ .
+ This package bundles a fixed Electron runtime and only production
+ dependencies; it does not install anything at runtime.

packaging/linux/debian/package.sh

@@ -0,0 +1,143 @@
+#!/usr/bin/env bash
+# Build a production StepForge .deb (and a matching portable tarball) from a
+# pruned, runtime-only tree.
+#
+# Unlike the old scripts/package-linux.sh this does NOT copy the development
+# node_modules, docs, prompts, examples, or stale audit files; it stages only
+# the app code plus a runtime dependency set (the fixed Electron runtime and
+# production npm deps), a real desktop entry, icons, MIME registration, and a
+# license. Architecture is detected, not hardcoded.
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../../.." && pwd)"
+cd "$ROOT_DIR"
+
+VERSION="$(node -p "require('./package.json').version")"
+MAINTAINER="${STEPFORGE_MAINTAINER:-StepForge <[email protected]>}"
+OUT_DIR="${STEPFORGE_PACKAGE_DIR:-$ROOT_DIR/build/artifacts}"
+mkdir -p "$OUT_DIR"
+
+# Map dpkg architecture to a Node-style label for the tarball name.
+DEB_ARCH="$(dpkg --print-architecture 2>/dev/null || echo amd64)"
+case "$DEB_ARCH" in
+  amd64) NODE_ARCH="x64" ;;
+  arm64) NODE_ARCH="arm64" ;;
+  *) NODE_ARCH="$DEB_ARCH" ;;
+esac
+
+# A packaged app must contain a fixed runtime; never install at build time from
+# within the package step, and never ship without node_modules.
+if [ ! -d "$ROOT_DIR/node_modules/electron/dist" ]; then
+  echo "error: node_modules/electron is missing. Run 'npm ci' before packaging." >&2
+  exit 1
+fi
+
+WORK_DIR="$(mktemp -d "${OUT_DIR%/}/.deb.XXXXXX")"
+trap 'rm -rf "$WORK_DIR"' EXIT
+APP_DIR="$WORK_DIR/opt/stepforge"
+mkdir -p "$APP_DIR" "$WORK_DIR/usr/bin" "$WORK_DIR/DEBIAN"
+mkdir -p "$WORK_DIR/usr/share/applications"
+mkdir -p "$WORK_DIR/usr/share/mime/packages"
+mkdir -p "$WORK_DIR/usr/share/doc/stepforge"
+
+# --- application code (runtime only) ----------------------------------------
+for item in app core exporters package.json package-lock.json; do
+  cp -a "$ROOT_DIR/$item" "$APP_DIR/$item"
+done
+
+# --- runtime node_modules ----------------------------------------------------
+# The fixed Electron runtime (needed at runtime even though it is a dev dep):
+mkdir -p "$APP_DIR/node_modules"
+cp -a "$ROOT_DIR/node_modules/electron" "$APP_DIR/node_modules/electron"
+# Production npm dependencies (tesseract.js + language data + transitive):
+while IFS= read -r dep; do
+  [ -n "$dep" ] || continue
+  rel="${dep#"$ROOT_DIR"/}"
+  [ "$rel" != "$dep" ] || continue          # only paths under the repo
+  [ -d "$dep" ] || continue
+  mkdir -p "$APP_DIR/$(dirname "$rel")"
+  cp -a "$dep" "$APP_DIR/$rel"
+done < <(npm ls --omit=dev --all --parseable 2>/dev/null | tail -n +2)
+
+# Guard: the development-only packaging toolchain must not have leaked in.
+if [ -d "$APP_DIR/node_modules/electron-builder" ] || [ -d "$APP_DIR/node_modules/app-builder-lib" ]; then
+  echo "error: build-only dependency leaked into the package payload." >&2
+  exit 1
+fi
+
+# --- launcher ----------------------------------------------------------------
+install -m 0755 "$ROOT_DIR/packaging/linux/common/launcher.sh" "$WORK_DIR/usr/bin/stepforge"
+
+# --- desktop entry, icons, MIME ---------------------------------------------
+install -m 0644 "$ROOT_DIR/packaging/linux/common/stepforge.desktop" "$WORK_DIR/usr/share/applications/stepforge.desktop"
+install -m 0644 "$ROOT_DIR/packaging/linux/common/stepforge-mime.xml" "$WORK_DIR/usr/share/mime/packages/stepforge.xml"
+for size in 16 32 48 64 128 256 512; do
+  icon="$ROOT_DIR/packaging/assets/icons/stepforge-${size}.png"
+  [ -f "$icon" ] || continue
+  dest="$WORK_DIR/usr/share/icons/hicolor/${size}x${size}/apps"
+  mkdir -p "$dest"
+  install -m 0644 "$icon" "$dest/stepforge.png"
+done
+
+# --- license + docs pointer --------------------------------------------------
+if [ -f "$ROOT_DIR/LICENSE" ]; then
+  install -m 0644 "$ROOT_DIR/LICENSE" "$WORK_DIR/usr/share/doc/stepforge/copyright"
+elif [ -f "$ROOT_DIR/docs/LICENSE" ]; then
+  install -m 0644 "$ROOT_DIR/docs/LICENSE" "$WORK_DIR/usr/share/doc/stepforge/copyright"
+fi
+
+# --- DEBIAN control + maintainer scripts ------------------------------------
+sed -e "s/@VERSION@/$VERSION/" -e "s/@ARCH@/$DEB_ARCH/" -e "s#@MAINTAINER@#$MAINTAINER#" \
+  "$ROOT_DIR/packaging/linux/debian/control.in" > "$WORK_DIR/DEBIAN/control"
+
+cat > "$WORK_DIR/DEBIAN/postinst" <<'POSTINST'
+#!/bin/sh
+set -e
+# Make the Chromium setuid sandbox helper usable so the app launches sandboxed.
+HELPER=/opt/stepforge/node_modules/electron/dist/chrome-sandbox
+if [ -e "$HELPER" ]; then
+  chown root:root "$HELPER" || true
+  chmod 4755 "$HELPER" || true
+fi
+# Refresh desktop/MIME/icon caches (best effort).
+if command -v update-desktop-database >/dev/null 2>&1; then update-desktop-database -q /usr/share/applications || true; fi
+if command -v update-mime-database >/dev/null 2>&1; then update-mime-database /usr/share/mime || true; fi
+if command -v gtk-update-icon-cache >/dev/null 2>&1; then gtk-update-icon-cache -q /usr/share/icons/hicolor || true; fi
+exit 0
+POSTINST
+
+cat > "$WORK_DIR/DEBIAN/prerm" <<'PRERM'
+#!/bin/sh
+set -e
+exit 0
+PRERM
+
+cat > "$WORK_DIR/DEBIAN/postrm" <<'POSTRM'
+#!/bin/sh
+set -e
+if [ "$1" = "remove" ] || [ "$1" = "purge" ]; then
+  if command -v update-desktop-database >/dev/null 2>&1; then update-desktop-database -q /usr/share/applications || true; fi
+  if command -v update-mime-database >/dev/null 2>&1; then update-mime-database /usr/share/mime || true; fi
+  if command -v gtk-update-icon-cache >/dev/null 2>&1; then gtk-update-icon-cache -q /usr/share/icons/hicolor || true; fi
+fi
+exit 0
+POSTRM
+chmod 0755 "$WORK_DIR/DEBIAN/postinst" "$WORK_DIR/DEBIAN/prerm" "$WORK_DIR/DEBIAN/postrm"
+
+# --- build the .deb ----------------------------------------------------------
+DEB_FILE="$OUT_DIR/stepforge_${VERSION}_${DEB_ARCH}.deb"
+if command -v fakeroot >/dev/null 2>&1; then
+  fakeroot dpkg-deb --build "$WORK_DIR" "$DEB_FILE" >/dev/null
+else
+  dpkg-deb --build "$WORK_DIR" "$DEB_FILE" >/dev/null
+fi
+
+# --- portable tarball (INCLUDES the launcher, unlike the old script) ---------
+TAR_FILE="$OUT_DIR/stepforge_${VERSION}_linux-${NODE_ARCH}.tar.gz"
+tar -C "$WORK_DIR" -czf "$TAR_FILE" opt usr/bin/stepforge usr/share/applications usr/share/mime usr/share/icons
+
+# --- checksums ---------------------------------------------------------------
+( cd "$OUT_DIR" && sha256sum "$(basename "$DEB_FILE")" "$(basename "$TAR_FILE")" > "stepforge_${VERSION}_${DEB_ARCH}.sha256" )
+
+echo "$DEB_FILE"
+echo "$TAR_FILE"

scripts/build-release.sh

@@ -14,7 +14,14 @@ mkdir -p "$BUILD_ROOT"
 
 bash "$ROOT_DIR/scripts/bootstrap-offline.sh"
 node "$ROOT_DIR/scripts/make-sample-guide.js" --root "$EXAMPLES_ROOT"
-STEPFORGE_PACKAGE_DIR="$ARTIFACT_DIR" bash "$ROOT_DIR/scripts/package-linux.sh" >/dev/null
+# Production Linux package: a pruned runtime tree with real desktop
+# integration. Requires node_modules (fails otherwise); never installs at
+# build time. Skipped only when the Electron runtime is genuinely absent.
+if [ -d "$ROOT_DIR/node_modules/electron/dist" ]; then
+  STEPFORGE_PACKAGE_DIR="$ARTIFACT_DIR" bash "$ROOT_DIR/packaging/linux/debian/package.sh" >/dev/null
+else
+  echo "[build-release] skipping Linux .deb: node_modules/electron missing (run npm ci)" >&2
+fi
 
 BUILD_ROOT="$BUILD_ROOT" \
 ARTIFACT_DIR="$ARTIFACT_DIR" \

scripts/linux/apt/install-build-deps.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# Install the BUILD toolchain for producing StepForge packages on apt-based
+# systems. These are for DEVELOPERS/packagers only and are never shipped inside
+# the end-user package.
+set -euo pipefail
+
+if ! command -v apt-get >/dev/null 2>&1; then
+  echo "This script is for apt-based systems (Debian/Ubuntu)." >&2
+  exit 1
+fi
+
+SUDO=""
+if [ "$(id -u)" -ne 0 ]; then SUDO="sudo"; fi
+
+PACKAGES=(
+  dpkg-dev fakeroot   # build the .deb
+  desktop-file-utils  # validate the .desktop entry
+  ca-certificates     # npm ci over https
+  xvfb                # headless smoke test under Xvfb
+)
+
+echo "Installing StepForge build dependencies via apt..."
+$SUDO apt-get update
+$SUDO apt-get install -y --no-install-recommends "${PACKAGES[@]}"
+
+cat <<'MSG'
+Done. Also install the pinned Node toolchain (see .nvmrc — Node 22.12+):
+  nvm install && nvm use     # or another Node 22 LTS install method
+Then, from the repo root:
+  npm ci
+  npm run package:linux:deb
+MSG

scripts/linux/apt/install-runtime-deps.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+# Install the RUNTIME libraries StepForge needs on apt-based systems
+# (Debian/Ubuntu). These are the shared libraries the packaged Electron runtime
+# links against, plus the X11/portal integration used for capture. This is for
+# END USERS installing from the tarball; the .deb declares the same set as
+# Depends so apt pulls them automatically.
+set -euo pipefail
+
+if ! command -v apt-get >/dev/null 2>&1; then
+  echo "This script is for apt-based systems (Debian/Ubuntu). Use the dnf script on Fedora." >&2
+  exit 1
+fi
+
+SUDO=""
+if [ "$(id -u)" -ne 0 ]; then SUDO="sudo"; fi
+
+PACKAGES=(
+  # Chromium/Electron shared libraries
+  libnss3 libnspr4 libatk1.0-0 libatk-bridge2.0-0 libcups2 libdrm2
+  libgtk-3-0 libgbm1 libasound2 libxkbcommon0 libatspi2.0-0
+  libxcomposite1 libxdamage1 libxfixes3 libxrandr2 libxshmfence1
+  # X11 per-click capture (marker-accurate) — X11 sessions only
+  xinput x11-utils
+  # Wayland screen-share via the XDG portal + PipeWire
+  xdg-desktop-portal pipewire
+)
+
+echo "Installing StepForge runtime dependencies via apt..."
+$SUDO apt-get update
+$SUDO apt-get install -y --no-install-recommends "${PACKAGES[@]}"
+echo "Done. StepForge runtime dependencies are installed."

scripts/make-icons.js

@@ -0,0 +1,69 @@
+#!/usr/bin/env node
+'use strict';
+
+// Generate the StepForge PNG icon set from original geometry using the repo's
+// own rasterizer + PNG writer (no external image tooling or third-party art).
+// Mirrors packaging/assets/stepforge.svg. Output: packaging/assets/icons/.
+
+const fs = require('node:fs');
+const path = require('node:path');
+const { createImage, fillRect, fillOval } = require('../core/raster');
+const { encodePng } = require('../core/png');
+
+const OUT_DIR = path.join(__dirname, '..', 'packaging', 'assets', 'icons');
+const SIZES = [16, 32, 48, 64, 128, 256, 512];
+
+const BG_TOP = [37, 99, 235, 255];
+const BG_BOTTOM = [30, 58, 138, 255];
+const WHITE = [255, 255, 255, 255];
+const SPARK = [250, 204, 21, 255];
+
+function lerp(a, b, t) {
+  return [
+    Math.round(a[0] + (b[0] - a[0]) * t),
+    Math.round(a[1] + (b[1] - a[1]) * t),
+    Math.round(a[2] + (b[2] - a[2]) * t),
+    255,
+  ];
+}
+
+function renderIcon(size) {
+  const img = createImage(size, size, [0, 0, 0, 0]);
+  const s = size / 256; // scale from the 256px reference design
+
+  // Rounded-square background approximated by a vertical gradient fill.
+  for (let y = 0; y < size; y += 1) {
+    fillRect(img, 0, y, size, 1, lerp(BG_TOP, BG_BOTTOM, y / size));
+  }
+
+  // Three ascending steps (x, y, w, h in reference px).
+  const steps = [
+    [52, 150, 52, 54],
+    [102, 116, 52, 88],
+    [152, 82, 52, 122],
+  ];
+  for (const [x, y, w, h] of steps) {
+    fillRect(img, Math.round(x * s), Math.round(y * s), Math.round(w * s), Math.round(h * s), WHITE);
+  }
+
+  // Capture spark on the top step.
+  const r = Math.max(2, Math.round(16 * s));
+  fillOval(img, Math.round(178 * s - r), Math.round(60 * s - r), r * 2, r * 2, SPARK);
+
+  return img;
+}
+
+function main() {
+  fs.mkdirSync(OUT_DIR, { recursive: true });
+  for (const size of SIZES) {
+    const png = encodePng(renderIcon(size));
+    fs.writeFileSync(path.join(OUT_DIR, `stepforge-${size}.png`), png);
+  }
+  // A conventional default name for the desktop entry / hicolor 256px slot.
+  fs.copyFileSync(path.join(OUT_DIR, 'stepforge-256.png'), path.join(OUT_DIR, 'stepforge.png'));
+  console.log(`wrote ${SIZES.length + 1} icons to ${OUT_DIR}`);
+}
+
+if (require.main === module) main();
+
+module.exports = { renderIcon, SIZES };

scripts/package-linux.sh

@@ -1,92 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
-VERSION="$(node -p "const pkg=require('${ROOT_DIR}/package.json'); pkg.buildVersion || pkg.version" 2>/dev/null || echo 0.0.0)"
-OUT_DIR="${STEPFORGE_PACKAGE_DIR:-$ROOT_DIR/build/artifacts}"
-mkdir -p "$OUT_DIR"
-WORK_DIR="$(mktemp -d "${OUT_DIR%/}/.pkg.XXXXXX")"
-APP_DIR="$WORK_DIR/opt/stepforge"
-
-cleanup() {
-  rm -rf "$WORK_DIR"
-}
-trap cleanup EXIT
-
-mkdir -p "$APP_DIR" "$WORK_DIR/usr/bin" "$WORK_DIR/DEBIAN"
-
-copy_item() {
-  local src="$1"
-  local dest="$2"
-  if [[ -e "$ROOT_DIR/$src" ]]; then
-    mkdir -p "$(dirname "$dest")"
-    cp -a "$ROOT_DIR/$src" "$dest"
-  fi
-}
-
-# Application payload: only the files needed to run the app.
-copy_item app "$APP_DIR/app"
-copy_item core "$APP_DIR/core"
-copy_item exporters "$APP_DIR/exporters"
-copy_item scripts "$APP_DIR/scripts"
-copy_item README.md "$APP_DIR/README.md"
-copy_item LICENSE "$APP_DIR/LICENSE"
-copy_item docs "$APP_DIR/docs"
-copy_item ai_prompts "$APP_DIR/ai_prompts"
-copy_item package.json "$APP_DIR/package.json"
-copy_item package-lock.json "$APP_DIR/package-lock.json"
-copy_item examples "$APP_DIR/examples"
-copy_item build/agent_audit.md "$APP_DIR/build/agent_audit.md"
-
-if [[ -d "$ROOT_DIR/node_modules" ]]; then
-  cp -a "$ROOT_DIR/node_modules" "$APP_DIR/node_modules"
-fi
-
-cat > "$WORK_DIR/usr/bin/stepforge" <<'EOF'
-#!/usr/bin/env sh
-APP_DIR=/opt/stepforge
-ELECTRON="$APP_DIR/node_modules/.bin/electron"
-SANDBOX_HELPER="$APP_DIR/node_modules/electron/dist/chrome-sandbox"
-cd "$APP_DIR" || exit 1
-if command -v stat >/dev/null 2>&1 && [ -e "$SANDBOX_HELPER" ]; then
-  helper_uid="$(stat -c '%u' "$SANDBOX_HELPER" 2>/dev/null || echo '')"
-  helper_mode="$(stat -c '%a' "$SANDBOX_HELPER" 2>/dev/null || echo '')"
-  if [ "$helper_uid" = "0" ] && [ -n "$helper_mode" ]; then
-    helper_mode_num=$((8#$helper_mode))
-    if [ $((helper_mode_num & 04000)) -ne 0 ]; then
-      exec "$ELECTRON" "$APP_DIR" "$@"
-    fi
-  fi
-fi
-printf '%s\n' '[stepforge] Electron sandbox helper is not configured for this install; starting with --no-sandbox' >&2
-exec "$ELECTRON" --no-sandbox "$APP_DIR" "$@"
-EOF
-chmod 0755 "$WORK_DIR/usr/bin/stepforge"
-
-cat > "$WORK_DIR/DEBIAN/control" <<EOF
-Package: stepforge
-Version: $VERSION
-Section: utils
-Priority: optional
-Architecture: amd64
-Depends: xinput
-Maintainer: StepForge <[email protected]>
-Description: Offline desktop guide capture and export tool
- A fully offline desktop app for step-by-step documentation, built for local
- capture, annotation, and export workflows.
-EOF
-
-DEB_FILE="$OUT_DIR/stepforge_${VERSION}_amd64.deb"
-TAR_FILE="$OUT_DIR/stepforge_${VERSION}_linux-x64.tar.gz"
-
-if command -v dpkg-deb >/dev/null 2>&1; then
-  dpkg-deb --build "$WORK_DIR" "$DEB_FILE" >/dev/null
-else
-  echo "dpkg-deb is not installed; skipping .deb build" >&2
-fi
-
-tar -C "$WORK_DIR/opt" -czf "$TAR_FILE" stepforge
-
-printf '%s\n' "$DEB_FILE"
-printf '%s\n' "$TAR_FILE"

tests/integration/linux/package-deb.test.sh

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+# Integration test: build the production .deb and assert it is a real,
+# runtime-only package — the right files present, and the dev tree / build
+# tooling / app docs absent. A package is NOT accepted merely because
+# dpkg-deb produced a file.
+#
+# Honest skip policy: skip ONLY when the prerequisites are genuinely absent
+# (not apt-based, dpkg-deb missing, or node_modules not installed). Once we
+# build, any structural failure fails the test.
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../../.." && pwd)"
+cd "$ROOT_DIR"
+
+if ! command -v dpkg-deb >/dev/null 2>&1; then
+  echo "package-deb SKIPPED: dpkg-deb not installed (not an apt-based build host)"
+  exit 0
+fi
+if [ ! -d "$ROOT_DIR/node_modules/electron/dist" ]; then
+  echo "package-deb SKIPPED: node_modules/electron missing (run npm ci first)"
+  exit 0
+fi
+
+OUT_DIR="$(mktemp -d)"
+trap 'rm -rf "$OUT_DIR"' EXIT
+
+DEB="$(STEPFORGE_PACKAGE_DIR="$OUT_DIR" bash packaging/linux/debian/package.sh | head -1)"
+if [ ! -f "$DEB" ]; then
+  echo "package-deb FAILED: builder did not produce a .deb" >&2
+  exit 1
+fi
+
+fail() { echo "package-deb FAILED: $1" >&2; exit 1; }
+
+listing="$(dpkg-deb -c "$DEB")"
+control="$(dpkg-deb -f "$DEB")"
+
+# Required install items.
+for needle in \
+  './usr/bin/stepforge' \
+  './usr/share/applications/stepforge.desktop' \
+  './usr/share/mime/packages/stepforge.xml' \
+  './usr/share/icons/hicolor/256x256/apps/stepforge.png' \
+  './opt/stepforge/node_modules/electron/dist/electron' \
+  './opt/stepforge/app/main.js' \
+  './usr/share/doc/stepforge/copyright'; do
+  echo "$listing" | grep -qF "$needle" || fail "missing packaged file: $needle"
+done
+
+# The development node_modules / build tooling must NOT be present.
+for banned in \
+  'node_modules/electron-builder' \
+  'node_modules/app-builder-lib' \
+  'node_modules/dmg-builder'; do
+  echo "$listing" | grep -qF "$banned" && fail "build-only dependency leaked: $banned" || true
+done
+
+# The app's own docs/prompts/examples must not be shipped.
+for banned in \
+  './opt/stepforge/docs/' \
+  './opt/stepforge/ai_prompts/' \
+  './opt/stepforge/examples/'; do
+  echo "$listing" | grep -qF "$banned" && fail "app extra shipped: $banned" || true
+done
+
+# Control metadata sanity.
+echo "$control" | grep -q '^Package: stepforge' || fail "control missing Package"
+echo "$control" | grep -q '^Depends:.*libnss3' || fail "control missing runtime Depends"
+echo "$control" | grep -Eq '^Architecture: (amd64|arm64)' || fail "control has no concrete Architecture"
+
+# Sandbox is set up, not disabled: postinst makes chrome-sandbox setuid.
+dpkg-deb --info "$DEB" | grep -q 'postinst' || fail "no postinst maintainer script"
+
+# The launcher must refuse an unsandboxed launch by default.
+grep -q 'STEPFORGE_ALLOW_NO_SANDBOX' packaging/linux/common/launcher.sh \
+  || fail "launcher does not gate --no-sandbox behind an explicit opt-in"
+
+echo "package-deb OK ($(basename "$DEB"), $(du -h "$DEB" | cut -f1))"

tests/unit/ai-network.test.js

@@ -181,6 +181,76 @@ test('shortcut detection still works with typed text disabled', () => {
   assert.equal(off.snapshotKeyContext().recentShortcut, 'Ctrl+T');
 });
 
+// ---- stale AI responses cannot overwrite user edits --------------------------
+
+test('an AI patch built from stale data does not clobber a mid-generation user edit', async (t) => {
+  const { GuideStore } = require('../../core/store');
+  const root = makeTmpDir('ai-stale-write');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'G' });
+  const step = store.addStep(guide.guideId, { title: 'original title' });
+
+  const service = new TextIntelService({
+    store,
+    settings: makeSettings(),
+    dataDir: root,
+    fetchImpl: async (url) => {
+      const pathname = new URL(url).pathname;
+      if (pathname === '/api/show') {
+        return { ok: true, json: async () => ({ capabilities: ['completion'] }) };
+      }
+      if (pathname === '/api/chat') {
+        // While the model "thinks", the user edits and saves the step.
+        const current = store.getStep(guide.guideId, step.stepId);
+        store.saveStep(guide.guideId, { ...current, title: 'user edit during generation' });
+        return {
+          ok: true,
+          json: async () => ({ message: { content: JSON.stringify({ title: 'AI title from stale context' }) } }),
+        };
+      }
+      throw new Error(`unexpected fetch: ${pathname}`);
+    },
+  });
+
+  const result = await service.generateStepPatch({ guideId: guide.guideId, stepId: step.stepId, target: 'title' });
+  assert.equal(result.ok, false);
+  assert.match(result.reason, /changed while AI was generating/i);
+  assert.equal(store.getStep(guide.guideId, step.stepId).title, 'user edit during generation');
+});
+
+test('an AI patch applies cleanly when nothing changed during generation', async (t) => {
+  const { GuideStore } = require('../../core/store');
+  const root = makeTmpDir('ai-clean-write');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'G' });
+  const step = store.addStep(guide.guideId, { title: '' });
+
+  const service = new TextIntelService({
+    store,
+    settings: makeSettings(),
+    dataDir: root,
+    fetchImpl: async (url) => {
+      const pathname = new URL(url).pathname;
+      if (pathname === '/api/show') {
+        return { ok: true, json: async () => ({ capabilities: ['completion'] }) };
+      }
+      if (pathname === '/api/chat') {
+        return {
+          ok: true,
+          json: async () => ({ message: { content: JSON.stringify({ title: 'Generated title' }) } }),
+        };
+      }
+      throw new Error(`unexpected fetch: ${pathname}`);
+    },
+  });
+
+  const result = await service.generateStepPatch({ guideId: guide.guideId, stepId: step.stepId, target: 'title' });
+  assert.equal(result.ok, true);
+  assert.equal(store.getStep(guide.guideId, step.stepId).title, 'Generated title');
+});
+
 // ---- source-level guards ----------------------------------------------------
 
 const fs = require('node:fs');

tests/unit/capture-fixes.test.js

@@ -0,0 +1,120 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const CaptureService = require('../../app/capture');
+
+function makeService({ settings: settingsOverrides, powerPolicy } = {}) {
+  const settingsData = {
+    'capture.mode': 'fullscreen',
+    'capture.delayMs': 0,
+    ...settingsOverrides,
+  };
+  return new CaptureService({
+    store: {},
+    settings: { get: (k) => (k in settingsData ? settingsData[k] : null) },
+    getWindow: () => null,
+    notify: () => {},
+    powerPolicy,
+    screenApi: {
+      getCursorScreenPoint: () => ({ x: 0, y: 0 }),
+      getAllDisplays: () => [],
+    },
+  });
+}
+
+// ---- region rect clamping (bug: out-of-bounds / negative drags) -------------
+
+test('overlayRectToImageRect scales, clamps, and normalizes selections', () => {
+  const svc = makeService();
+  const display = { bounds: { x: 0, y: 0, width: 100, height: 100 } };
+  const imgSize = { width: 200, height: 200 }; // 2x DPI
+
+  // Simple selection: display px -> image px (2x).
+  assert.deepEqual(
+    svc.overlayRectToImageRect({ x: 10, y: 20, w: 30, h: 40 }, display, imgSize),
+    { x: 20, y: 40, width: 60, height: 80 }
+  );
+
+  // Negative-size drag (drawn up/left) normalizes to a positive rect.
+  assert.deepEqual(
+    svc.overlayRectToImageRect({ x: 40, y: 40, w: -20, h: -20 }, display, imgSize),
+    { x: 40, y: 40, width: 40, height: 40 }
+  );
+
+  // Selection larger than the screen is clamped to the image bounds.
+  const clamped = svc.overlayRectToImageRect({ x: -10, y: -10, w: 200, h: 200 }, display, imgSize);
+  assert.deepEqual(clamped, { x: 0, y: 0, width: 200, height: 200 });
+
+  // Degenerate selections return null instead of an out-of-bounds crop.
+  assert.equal(svc.overlayRectToImageRect({ x: 0, y: 0, w: 0, h: 0 }, display, imgSize), null);
+  assert.equal(svc.overlayRectToImageRect({ x: 999, y: 999, w: 10, h: 10 }, display, imgSize), null);
+  assert.equal(svc.overlayRectToImageRect(null, display, imgSize), null);
+});
+
+// ---- power ownership follows recording state --------------------------------
+
+test('the power blocker is held only while actively recording', () => {
+  const calls = [];
+  const powerPolicy = { setRecording: (on) => calls.push(on) };
+  const svc = makeService({ powerPolicy });
+
+  // startSession begins PAUSED — must not hold power.
+  svc.startSession('g1', { intervalSec: 0 });
+  assert.deepEqual(calls, [], 'a paused new session must not start the power blocker');
+
+  // Resume records -> power on. (togglePause(false) arms recording.)
+  svc.togglePause(false);
+  assert.deepEqual(calls, [true]);
+
+  // Pause -> power off. This is the tray/second-instance path that used to leak.
+  svc.togglePause(true);
+  assert.deepEqual(calls, [true, false]);
+
+  // Resume again -> on, finish -> off.
+  svc.togglePause(false);
+  svc.finishSession();
+  assert.deepEqual(calls, [true, false, true, false]);
+});
+
+test('finishSession releases power even if it was recording', () => {
+  const calls = [];
+  const svc = makeService({ powerPolicy: { setRecording: (on) => calls.push(on) } });
+  svc.startSession('g1', { intervalSec: 0 });
+  svc.togglePause(false);
+  calls.length = 0;
+  svc.finishSession();
+  assert.deepEqual(calls, [false]);
+});
+
+// ---- explicit click-source reporting ----------------------------------------
+
+test('click source is unavailable outside a session and after stop', () => {
+  const svc = makeService();
+  assert.equal(svc.state().clickSource, 'unavailable');
+  assert.equal(svc.state().clickCapture, undefined); // no session -> no field
+  svc.clickSource = 'evdev-x11';
+  svc.stopClickWatcher();
+  assert.equal(svc.clickSource, 'unavailable');
+});
+
+test('state reports clickCapture true for a non-process (evdev) source', () => {
+  const svc = makeService();
+  svc.session = { guideId: 'g', paused: false, count: 0, intervalSec: 0 };
+  // evdev has no child process; the old Boolean(clickWatcher) reported false.
+  svc.clickSource = 'evdev-wayland';
+  const st = svc.state();
+  assert.equal(st.clickCapture, true);
+  assert.equal(st.clickSource, 'evdev-wayland');
+});
+
+// ---- drain never hangs quit -------------------------------------------------
+
+test('drainPendingClicks resolves within the deadline even if the queue hangs', async () => {
+  const svc = makeService();
+  svc.clickQueue = new Promise(() => {}); // never settles
+  const start = Date.now();
+  await svc.drainPendingClicks(60);
+  assert.ok(Date.now() - start < 1000, 'drain must not block on a hung queue');
+});

tests/unit/capture.test.js

@@ -68,7 +68,9 @@ function makeFrame(name, ageMs = 0, overrides = {}) {
 // ---- fresh-shot fallback path ----------------------------------------------
 
 test('click-triggered session capture uses the low-latency hide pause', async () => {
-  const service = makeService();
+  // The fresh-shot fallback only runs in non-strict (balanced) mode; strict
+  // mode skips rather than storing a post-click shot.
+  const service = makeService({ settings: { 'capture.strictClickFrames': false } });
   service.session = { guideId: 'guide-1', paused: false, count: 0, intervalSec: 0 };
 
   let seenOptions = null;
@@ -1006,7 +1008,9 @@ test('a buffered frame from a different display is ignored for click capture', a
 });
 
 test('a stale buffered frame is not reused — the click falls back to a fresh shot', async () => {
-  const service = makeService();
+  // Balanced (non-strict) mode: a stale frame is rejected and the click takes
+  // the fresh-shot fallback. (Strict mode skips instead — see below.)
+  const service = makeService({ settings: { 'capture.strictClickFrames': false } });
   service.session = { guideId: 'guide-stale', paused: false, count: 0, intervalSec: 0 };
   service.latestFrame = makeFrame('stale-png', 10_000);
 
@@ -1022,12 +1026,12 @@ test('a stale buffered frame is not reused — the click falls back to a fresh s
   assert.equal(shootCalled, true, 'a stale buffered frame must not be reused');
 });
 
-test('strict mode: a frame whose grab started after the click is rejected', async () => {
-  // This replaces the old "idle click waits for the imminent loop frame"
-  // behavior: a grab that begins after the click can already show the
-  // click's effects, so strict mode takes the explicit fresh-shot fallback
-  // instead of passing it off as the click-time screen.
-  const service = makeService();
+test('strict mode: no pre-click frame is skipped, never stored as a post-click shot', async () => {
+  // A grab that begins after the click can already show the click's effects.
+  // Strict mode's promise is that a stored step never shows the post-click
+  // screen, so when no pre-click frame qualifies it SKIPS with a diagnostic
+  // rather than taking a fresh (post-click) shot.
+  const service = makeService(); // strict is the default
   service.session = { guideId: 'guide-strict', paused: false, count: 0, intervalSec: 0 };
   service.frameLoopRunning = true;
   service.frameLoopInFlight = false; // nothing in flight at click time
@@ -1041,11 +1045,18 @@ test('strict mode: a frame whose grab started after the click is rejected', asyn
     shootCalled = true;
     return { ok: true, step: { stepId: 'fresh-step' } };
   };
+  const diagnostics = [];
+  service.notify = (channel, payload) => {
+    if (channel === 'capture:diagnostic') diagnostics.push(payload);
+  };
 
   const result = await service.sessionCapture('click', { x: 1, y: 1 }, { at: clickAt });
 
-  assert.equal(result.ok, true);
-  assert.equal(shootCalled, true);
+  assert.equal(result.ok, false);
+  assert.match(result.reason, /strict/i);
+  assert.equal(shootCalled, false, 'strict mode must not store a post-click shot');
+  assert.equal(diagnostics.length, 1);
+  assert.equal(diagnostics[0].kind, 'strict-click-skipped');
 });
 
 test('balanced mode keeps the legacy slack: an imminent post-click frame is accepted', async () => {
@@ -1183,7 +1194,9 @@ test('click frames come from the stream backend when it is active', async () =>
 });
 
 test('a stream backend with no qualifying frame falls through to the fresh-shot path', async () => {
-  const service = makeService();
+  // Balanced (non-strict) mode: the fresh-shot fallback runs. Strict mode
+  // would skip rather than store a post-click shot.
+  const service = makeService({ settings: { 'capture.strictClickFrames': false } });
   service.session = { guideId: 'guide-stream-miss', paused: false, count: 0, intervalSec: 0 };
   service.streamBackend = {
     isActive: () => true,
@@ -1279,6 +1292,8 @@ test('click capture marks the click-time cursor position', async () => {
     if (key === 'capture.clickMarker') return true;
     if (key === 'capture.clickMarkerColor') return '#E5484D';
     if (key === 'editor.focusedViewDefaultForNewSteps') return false;
+    // Exercise the fresh-shot fallback: strict mode would skip instead.
+    if (key === 'capture.strictClickFrames') return false;
     return null;
   };
   service.session = { guideId: 'guide-4', paused: false, count: 0, intervalSec: 0 };

tests/unit/packaging-linux.test.js

@@ -0,0 +1,97 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const ROOT = path.resolve(__dirname, '..', '..');
+const read = (rel) => fs.readFileSync(path.join(ROOT, rel), 'utf8');
+const exists = (rel) => fs.existsSync(path.join(ROOT, rel));
+
+// These are structural checks that run in the normal (cross-platform) unit
+// suite so the Linux packaging config can't rot silently; the actual .deb
+// build/inspection lives in tests/integration/linux/package-deb.test.sh.
+
+test('Linux packaging files exist in their expected separate locations', () => {
+  for (const f of [
+    'packaging/linux/debian/package.sh',
+    'packaging/linux/debian/control.in',
+    'packaging/linux/common/stepforge.desktop',
+    'packaging/linux/common/stepforge-mime.xml',
+    'packaging/linux/common/launcher.sh',
+    'scripts/linux/apt/install-runtime-deps.sh',
+    'scripts/linux/apt/install-build-deps.sh',
+    'docs/linux/apt.md',
+    'tests/integration/linux/package-deb.test.sh',
+  ]) {
+    assert.ok(exists(f), `expected ${f} to exist`);
+  }
+});
+
+test('the old non-production package-linux.sh is gone', () => {
+  assert.equal(exists('scripts/package-linux.sh'), false);
+});
+
+test('the desktop entry is valid and app-branded', () => {
+  const desktop = read('packaging/linux/common/stepforge.desktop');
+  assert.match(desktop, /^\[Desktop Entry\]/);
+  assert.match(desktop, /^Type=Application$/m);
+  assert.match(desktop, /^Exec=stepforge %U$/m);
+  assert.match(desktop, /^Icon=stepforge$/m);
+  assert.match(desktop, /^Categories=.+;$/m);
+  assert.match(desktop, /MimeType=application\/x-stepforge-guide/);
+});
+
+test('the control template declares runtime deps, no hardcoded arch, real maintainer slot', () => {
+  const control = read('packaging/linux/debian/control.in');
+  assert.match(control, /^Architecture: @ARCH@$/m, 'arch must be templated, not hardcoded');
+  assert.match(control, /^Depends:.*libnss3/m);
+  assert.match(control, /@VERSION@/);
+  assert.match(control, /@MAINTAINER@/);
+  // The false "fully offline" wording must not reappear here.
+  assert.doesNotMatch(control, /fully offline/i);
+});
+
+test('the launcher refuses an unsandboxed launch unless explicitly opted in', () => {
+  const launcher = read('packaging/linux/common/launcher.sh');
+  assert.match(launcher, /STEPFORGE_ALLOW_NO_SANDBOX/);
+  // It must not unconditionally exec with --no-sandbox.
+  assert.doesNotMatch(launcher, /^exec .*--no-sandbox/m);
+  // It never installs anything at runtime.
+  assert.doesNotMatch(launcher, /npm (install|ci|rebuild)/);
+});
+
+test('the package builder requires node_modules and guards against dev-dep leaks', () => {
+  const script = read('packaging/linux/debian/package.sh');
+  assert.match(script, /node_modules\/electron\/dist/);
+  assert.match(script, /npm ls --omit=dev/);
+  assert.match(script, /electron-builder/); // the leak guard references it
+  assert.match(script, /dpkg --print-architecture/); // arch detected, not hardcoded
+  assert.doesNotMatch(script, /cp -a "\$ROOT_DIR\/node_modules" /); // never copy the whole dev tree
+});
+
+test('apt setup scripts target apt and keep build vs runtime deps separate', () => {
+  const runtime = read('scripts/linux/apt/install-runtime-deps.sh');
+  const build = read('scripts/linux/apt/install-build-deps.sh');
+  assert.match(runtime, /apt-get/);
+  assert.match(runtime, /libnss3/);
+  assert.doesNotMatch(runtime, /dpkg-dev|fakeroot/, 'runtime script must not install build tools');
+  assert.match(build, /dpkg-dev/);
+  assert.match(build, /fakeroot/);
+});
+
+test('an original icon set is generated (not a placeholder/third-party asset)', () => {
+  assert.ok(exists('packaging/assets/stepforge.svg'));
+  assert.ok(exists('scripts/make-icons.js'));
+  // The generated PNGs are committed for packaging.
+  for (const size of [16, 48, 256]) {
+    assert.ok(exists(`packaging/assets/icons/stepforge-${size}.png`), `icon ${size} missing`);
+  }
+  // Regenerate the 256px icon and confirm the generator is deterministic and
+  // produces a valid PNG (starts with the PNG signature).
+  const { renderIcon } = require('../../scripts/make-icons');
+  const { encodePng } = require('../../core/png');
+  const png = encodePng(renderIcon(256));
+  assert.deepEqual([...png.subarray(0, 4)], [0x89, 0x50, 0x4e, 0x47]);
+});

tests/unit/platform.test.js

@@ -0,0 +1,139 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const { detectPlatform, createWindowContextProvider, detectCapabilities } = require('../../app/platform');
+const { assertWindowContextProvider, CLICK_SOURCES } = require('../../app/platform/interfaces');
+const { detectLinuxCapabilities, detectSessionType } = require('../../app/platform/linux/diagnostics');
+
+// ---- platform selection -----------------------------------------------------
+
+test('detectPlatform maps process.platform to an adapter family', () => {
+  assert.equal(detectPlatform('win32'), 'windows');
+  assert.equal(detectPlatform('darwin'), 'darwin');
+  assert.equal(detectPlatform('linux'), 'linux');
+  assert.equal(detectPlatform('sunos'), 'unsupported');
+});
+
+test('the factory returns a valid WindowContextProvider for every OS', () => {
+  for (const platform of ['win32', 'darwin', 'linux', 'sunos']) {
+    const provider = createWindowContextProvider({ platform });
+    assert.doesNotThrow(() => assertWindowContextProvider(provider));
+    assert.equal(typeof provider.collect, 'function');
+  }
+});
+
+test('an unsupported platform provider returns an empty context, never throws', async () => {
+  const provider = createWindowContextProvider({ platform: 'sunos' });
+  assert.deepEqual(await provider.collect(), { appName: '', windowTitle: '' });
+});
+
+test('the shared code delegates window context to the injected provider', async () => {
+  // The text-intel service must consume the provider, not branch on platform.
+  const { TextIntelService } = require('../../app/text-intel');
+  const { makeTmpDir, rmrf } = require('./helpers');
+  const root = makeTmpDir('platform-ctx');
+  let sawPoint = null;
+  const service = new TextIntelService({
+    store: { settingsDir: root },
+    settings: { get: () => null },
+    dataDir: root,
+    windowContextProvider: {
+      async collect(osPoint) { sawPoint = osPoint; return { appName: 'TestApp', windowTitle: 'Test Window' }; },
+    },
+  });
+  const ctx = await service.collectForegroundWindowContext({ x: 5, y: 6 });
+  assert.deepEqual(ctx, { appName: 'TestApp', windowTitle: 'Test Window' });
+  assert.deepEqual(sawPoint, { x: 5, y: 6 });
+  rmrf(root);
+});
+
+// ---- Linux diagnostics ------------------------------------------------------
+
+test('session type prefers XDG_SESSION_TYPE then display env', () => {
+  assert.equal(detectSessionType({ XDG_SESSION_TYPE: 'wayland' }), 'wayland');
+  assert.equal(detectSessionType({ XDG_SESSION_TYPE: 'x11' }), 'x11');
+  assert.equal(detectSessionType({ WAYLAND_DISPLAY: 'wayland-0' }), 'wayland');
+  assert.equal(detectSessionType({ DISPLAY: ':0' }), 'x11');
+  assert.equal(detectSessionType({}), 'unknown');
+});
+
+test('X11 with xinput reports marker-capable per-click capture', () => {
+  const caps = detectLinuxCapabilities({
+    env: { XDG_SESSION_TYPE: 'x11', DISPLAY: ':0', DBUS_SESSION_BUS_ADDRESS: 'unix:x' },
+    hasBinary: (n) => n === 'xinput' || n === 'xprop',
+    existsSync: () => false,
+    readdirSync: () => [],
+  });
+  assert.equal(caps.isWayland, false);
+  assert.equal(caps.clickCapture, 'x11-xinput');
+  assert.equal(caps.screenCapture, 'x11-direct');
+});
+
+test('Wayland without PipeWire reports an actionable message', () => {
+  const caps = detectLinuxCapabilities({
+    env: { XDG_SESSION_TYPE: 'wayland', WAYLAND_DISPLAY: 'wayland-0' },
+    hasBinary: () => false,
+    existsSync: () => false,
+    readdirSync: () => [],
+  });
+  assert.equal(caps.isWayland, true);
+  assert.equal(caps.screenCapture, 'wayland-portal');
+  assert.ok(caps.messages.some((m) => /PipeWire|portal/i.test(m)));
+});
+
+test('no click source falls back to hotkey/interval with a message', () => {
+  const caps = detectLinuxCapabilities({
+    env: { XDG_SESSION_TYPE: 'x11', DISPLAY: ':0' },
+    hasBinary: () => false, // no xinput
+    existsSync: () => false,
+    readdirSync: () => [], // no readable input devices
+  });
+  assert.equal(caps.clickCapture, 'hotkey-or-interval-only');
+  assert.ok(caps.messages.some((m) => /hotkey|interval/i.test(m)));
+});
+
+test('readable evdev devices enable an evdev click source', () => {
+  const caps = detectLinuxCapabilities({
+    env: { XDG_SESSION_TYPE: 'wayland', WAYLAND_DISPLAY: 'wayland-0' },
+    hasBinary: (n) => n === 'pipewire',
+    existsSync: () => true,
+    readdirSync: () => ['event0', 'event1', 'mouse0'],
+  });
+  // event0/event1 are readable (accessSync is real, but /dev/input/eventN
+  // likely won't exist in CI; the profile still resolves without throwing).
+  assert.ok(['evdev-wayland', 'hotkey-or-interval-only'].includes(caps.clickCapture));
+  assert.equal(caps.os, 'linux');
+});
+
+// ---- capability facade ------------------------------------------------------
+
+test('detectCapabilities returns a Linux profile with valid click source', () => {
+  const caps = detectCapabilities({ platform: 'linux', env: { XDG_SESSION_TYPE: 'x11', DISPLAY: ':0' } });
+  assert.equal(caps.os, 'linux');
+});
+
+test('detectCapabilities reports windows-hook for Windows', () => {
+  const caps = detectCapabilities({ platform: 'win32', env: {} });
+  assert.equal(caps.os, 'windows');
+  assert.equal(caps.clickCapture, 'windows-hook');
+});
+
+test('every documented click source is a known token', () => {
+  for (const s of ['windows-hook', 'x11', 'evdev-x11', 'evdev-wayland', 'wayland-portal', 'hotkey', 'interval', 'unavailable']) {
+    assert.ok(CLICK_SOURCES.includes(s));
+  }
+});
+
+// ---- refactor guard ---------------------------------------------------------
+
+const fs = require('node:fs');
+const path = require('node:path');
+
+test('text-intel no longer branches on process.platform for window context', () => {
+  const src = fs.readFileSync(path.join(__dirname, '..', '..', 'app', 'text-intel.js'), 'utf8');
+  assert.doesNotMatch(src, /collectWindowsWindowContext|collectMacWindowContext|collectLinuxWindowContext/);
+  assert.doesNotMatch(src, /process\.platform === 'win32'/);
+  assert.match(src, /this\.windowContext\.collect/);
+});

tests/unit/recovery-hardening.test.js

@@ -0,0 +1,299 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+const zlib = require('node:zlib');
+
+const { GuideStore } = require('../../core/store');
+const { SearchIndex } = require('../../core/search');
+const { unzipSync, zipSync, crc32 } = require('../../core/zip');
+const { exportGuideArchive, importGuideArchive } = require('../../core/archive');
+const { createSnapshot, restoreSnapshot, autoSnapshotIfDue } = require('../../core/snapshots');
+const { acquireLock, releaseLock } = require('../../core/locks');
+const { makeTmpDir, rmrf, TINY_PNG } = require('./helpers');
+
+// ---- ZIP bomb / resource limits ---------------------------------------------
+
+test('unzip rejects an archive that declares too many entries', () => {
+  const many = [];
+  for (let i = 0; i < 20; i += 1) many.push({ name: `f${i}.txt`, data: 'x' });
+  const buf = zipSync(many);
+  assert.throws(() => unzipSync(buf, { limits: { maxEntries: 5 } }), /too many entries/);
+});
+
+test('unzip rejects an entry whose declared size exceeds the per-entry limit', () => {
+  const buf = zipSync([{ name: 'big.txt', data: Buffer.alloc(1000, 65) }]);
+  assert.throws(() => unzipSync(buf, { limits: { maxEntryUncompressed: 100 } }), /entry too large/);
+});
+
+test('unzip caps inflation so a deflate bomb cannot exhaust memory', () => {
+  // A hand-built entry whose deflate stream expands far past the cap. The
+  // maxOutputLength guard must abort inflation rather than allocating it all.
+  const bomb = Buffer.alloc(10 * 1024 * 1024, 0); // 10 MiB of zeros -> tiny deflate
+  const raw = zlib.deflateRawSync(bomb, { level: 9 });
+  const name = 'bomb';
+  const nameBuf = Buffer.from(name);
+  const local = Buffer.alloc(30);
+  local.writeUInt32LE(0x04034b50, 0);
+  local.writeUInt16LE(20, 4);
+  local.writeUInt16LE(0x0800, 6);
+  local.writeUInt16LE(8, 8); // deflate
+  local.writeUInt32LE(crc32(bomb), 14);
+  local.writeUInt32LE(raw.length, 18);
+  local.writeUInt32LE(bomb.length, 22);
+  local.writeUInt16LE(nameBuf.length, 26);
+  const central = Buffer.alloc(46);
+  central.writeUInt32LE(0x02014b50, 0);
+  central.writeUInt16LE(20, 4);
+  central.writeUInt16LE(20, 6);
+  central.writeUInt16LE(0x0800, 8);
+  central.writeUInt16LE(8, 10);
+  central.writeUInt32LE(crc32(bomb), 16);
+  central.writeUInt32LE(raw.length, 20);
+  central.writeUInt32LE(bomb.length, 24);
+  central.writeUInt16LE(nameBuf.length, 28);
+  central.writeUInt32LE(0, 42);
+  const localBlock = Buffer.concat([local, nameBuf, raw]);
+  const centralBlock = Buffer.concat([central, nameBuf]);
+  const eocd = Buffer.alloc(22);
+  eocd.writeUInt32LE(0x06054b50, 0);
+  eocd.writeUInt16LE(1, 8);
+  eocd.writeUInt16LE(1, 10);
+  eocd.writeUInt32LE(centralBlock.length, 12);
+  eocd.writeUInt32LE(localBlock.length, 16);
+  const buf = Buffer.concat([localBlock, centralBlock, eocd]);
+
+  assert.throws(() => unzipSync(buf, { limits: { maxEntryUncompressed: 64 * 1024 } }));
+});
+
+// ---- transactional archive import -------------------------------------------
+
+test('a corrupt step aborts the import leaving no partial guide', (t) => {
+  const root = makeTmpDir('import-atomic');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+
+  const guide = store.createGuide({ title: 'Src' });
+  store.addStep(guide.guideId, { title: 'S1' }, TINY_PNG, { width: 1, height: 1 });
+  const archiveFile = path.join(root, 'out.sfgz');
+  exportGuideArchive(store, guide.guideId, archiveFile);
+
+  // Corrupt the exported step so validation fails during import.
+  const { unzipSync: uz } = require('../../core/zip');
+  const entries = uz(fs.readFileSync(archiveFile));
+  const tampered = entries.map((e) => {
+    if (e.name.endsWith('step.json')) {
+      const obj = JSON.parse(e.data.toString('utf8'));
+      // Corrupt the image size to non-finite values — validateStep rejects
+      // an image step with an invalid size.
+      obj.image = { originalPath: 'original.png', workingPath: 'working.png', size: { width: 'x', height: null } };
+      return { name: e.name, data: Buffer.from(JSON.stringify(obj)) };
+    }
+    return { name: e.name, data: e.data };
+  });
+  fs.writeFileSync(archiveFile, zipSync(tampered));
+
+  const before = store.listGuides().length;
+  assert.throws(() => importGuideArchive(store, archiveFile, { mode: 'copy' }));
+  // No partial guide was left behind, and no staging dir remains.
+  assert.equal(store.listGuides().length, before);
+  const leftover = fs.readdirSync(store.guidesDir).filter((n) => n.includes('.importing'));
+  assert.deepEqual(leftover, []);
+});
+
+test('a valid archive imports cleanly', (t) => {
+  const root = makeTmpDir('import-ok');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'Src' });
+  store.addStep(guide.guideId, { title: 'S1' }, TINY_PNG, { width: 1, height: 1 });
+  const archiveFile = path.join(root, 'out.sfgz');
+  exportGuideArchive(store, guide.guideId, archiveFile);
+
+  const imported = importGuideArchive(store, archiveFile, { mode: 'copy' });
+  assert.equal(imported.title, 'Src');
+  assert.equal(imported.stepsOrder.length, 1);
+});
+
+// ---- atomic snapshot restore ------------------------------------------------
+
+test('restoring a corrupt snapshot never destroys the live guide', (t) => {
+  const root = makeTmpDir('snap-atomic');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'Live' });
+  store.addStep(guide.guideId, { title: 'keep me' }, TINY_PNG, { width: 1, height: 1 });
+  const snap = createSnapshot(store, guide.guideId, { label: 'good' });
+
+  // Corrupt the snapshot zip so restore must abort.
+  const snapFile = path.join(store.guideDir(guide.guideId), 'history', 'snapshots', snap);
+  fs.writeFileSync(snapFile, Buffer.from('not a zip at all'));
+
+  assert.throws(() => restoreSnapshot(store, guide.guideId, snap), /restore aborted|invalid|zip/i);
+  // The live guide and its step are intact.
+  const after = store.getGuide(guide.guideId);
+  assert.equal(after.title, 'Live');
+  assert.equal(after.stepsOrder.length, 1);
+});
+
+test('restoring a valid snapshot swaps content and keeps history', (t) => {
+  const root = makeTmpDir('snap-ok');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'V1' });
+  const s1 = store.addStep(guide.guideId, { title: 'first' }, TINY_PNG, { width: 1, height: 1 });
+  const snap = createSnapshot(store, guide.guideId, { label: 'v1' });
+
+  // Change the guide, then restore.
+  store.saveGuide({ ...store.getGuide(guide.guideId), title: 'V2' });
+  store.deleteStep(guide.guideId, s1.stepId);
+  assert.equal(store.getGuide(guide.guideId).title, 'V2');
+
+  const restored = restoreSnapshot(store, guide.guideId, snap);
+  assert.equal(restored.title, 'V1');
+  assert.equal(restored.stepsOrder.length, 1);
+  // history/ survived the restore (pre-restore snapshot exists too).
+  assert.ok(fs.existsSync(path.join(store.guideDir(guide.guideId), 'history')));
+});
+
+// ---- atomic locks -----------------------------------------------------------
+
+test('another process holding a fresh lock is a conflict; release-by-token frees ours', (t) => {
+  const root = makeTmpDir('lock');
+  t.after(() => rmrf(root));
+  const { lockPathFor } = require('../../core/locks');
+  const target = path.join(root, 'shared.sfgz');
+  fs.writeFileSync(target, 'x');
+
+  // Simulate a different process already holding a fresh lock.
+  fs.writeFileSync(lockPathFor(target), JSON.stringify({
+    host: 'other-host', user: 'someone-else', pid: 999999,
+    token: 'their-token', acquiredAt: new Date().toISOString(),
+  }));
+
+  const attempt = acquireLock(target);
+  assert.equal(attempt.acquired, false);
+  assert.ok(attempt.conflict);
+  // We must not be able to release their lock with a guessed/absent token.
+  assert.equal(releaseLock(target, { token: 'wrong' }), false);
+
+  // Force-steal (user confirmed), then release by our own acquisition token.
+  const stolen = acquireLock(target, { force: true });
+  assert.equal(stolen.acquired, true);
+  assert.equal(releaseLock(target, { lock: stolen.lock }), true);
+  assert.equal(acquireLock(target).acquired, true);
+});
+
+test('the same process can re-acquire its own lock', (t) => {
+  const root = makeTmpDir('lock-reacquire');
+  t.after(() => rmrf(root));
+  const target = path.join(root, 'shared.sfgz');
+  fs.writeFileSync(target, 'x');
+  assert.equal(acquireLock(target).acquired, true);
+  // Same process, second acquire: not a conflict.
+  assert.equal(acquireLock(target).acquired, true);
+});
+
+test('force steal takes over a held lock', (t) => {
+  const root = makeTmpDir('lock-force');
+  t.after(() => rmrf(root));
+  const target = path.join(root, 'shared.sfgz');
+  fs.writeFileSync(target, 'x');
+  acquireLock(target);
+  const stolen = acquireLock(target, { force: true });
+  assert.equal(stolen.acquired, true);
+});
+
+// ---- search reconcile -------------------------------------------------------
+
+test('reconcile rebuilds a missing index from the store', (t) => {
+  const root = makeTmpDir('search-rebuild');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'Password reset guide' });
+  store.addStep(guide.guideId, { title: 'Open admin portal' }, TINY_PNG, { width: 1, height: 1 });
+
+  // A brand-new index (nothing persisted) must recover by reconciling.
+  const index = new SearchIndex(store.indexDir);
+  const summary = index.reconcile(store);
+  assert.equal(summary.reindexed, 1);
+  assert.ok(index.search('password').length > 0);
+});
+
+test('reconcile drops entries for deleted guides and reindexes changed ones', (t) => {
+  const root = makeTmpDir('search-reconcile');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const g1 = store.createGuide({ title: 'alpha guide' });
+  const g2 = store.createGuide({ title: 'beta guide' });
+  const index = new SearchIndex(store.indexDir);
+  index.reconcile(store);
+  assert.ok(index.search('alpha').length > 0);
+
+  // Delete g1 out from under the index and change g2's title.
+  store.deleteGuide(g1.guideId);
+  store.saveGuide({ ...store.getGuide(g2.guideId), title: 'beta renamed gamma' });
+
+  const summary = index.reconcile(store);
+  assert.equal(index.search('alpha').length, 0, 'deleted guide is gone from search');
+  assert.ok(index.search('gamma').length > 0, 'changed guide is reindexed');
+  assert.equal(summary.removed, 1);
+});
+
+test('a corrupt index file resets to a recoverable status', (t) => {
+  const root = makeTmpDir('search-corrupt');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  store.createGuide({ title: 'recoverable' });
+  fs.mkdirSync(store.indexDir, { recursive: true });
+  fs.writeFileSync(path.join(store.indexDir, 'search-index.json'), '{ corrupt json');
+
+  const index = new SearchIndex(store.indexDir);
+  const summary = index.reconcile(store);
+  assert.equal(summary.status, 'reset');
+  assert.ok(index.search('recoverable').length > 0);
+});
+
+// ---- automatic backups ------------------------------------------------------
+
+test('autoSnapshotIfDue takes a snapshot every N saves and prunes', (t) => {
+  const root = makeTmpDir('auto-backup');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'G' });
+  const settings = {
+    get: (k) => ({ automatic: true, everyNSaves: 3, keepLast: 2 }[k.replace('backups.', '')] ?? ({ backups: { automatic: true, everyNSaves: 3, keepLast: 2 } }[k])),
+  };
+  // The helper reads settings.get('backups'):
+  const s = { get: (k) => (k === 'backups' ? { automatic: true, everyNSaves: 3, keepLast: 2 } : null) };
+
+  const dir = path.join(store.guideDir(guide.guideId), 'history', 'snapshots');
+  const count = () => (fs.existsSync(dir) ? fs.readdirSync(dir).filter((n) => n.endsWith('.zip')).length : 0);
+
+  assert.equal(autoSnapshotIfDue(store, guide.guideId, s), null); // 1
+  assert.equal(autoSnapshotIfDue(store, guide.guideId, s), null); // 2
+  assert.equal(autoSnapshotIfDue(store, guide.guideId, s), true); // 3 -> snapshot
+  assert.equal(count(), 1);
+  autoSnapshotIfDue(store, guide.guideId, s); // 1
+  autoSnapshotIfDue(store, guide.guideId, s); // 2
+  autoSnapshotIfDue(store, guide.guideId, s); // 3 -> snapshot
+  assert.equal(count(), 2);
+  autoSnapshotIfDue(store, guide.guideId, s);
+  autoSnapshotIfDue(store, guide.guideId, s);
+  autoSnapshotIfDue(store, guide.guideId, s); // 3rd snapshot, pruned to keepLast=2
+  assert.equal(count(), 2, 'pruned to keepLast');
+});
+
+test('autoSnapshotIfDue is a no-op when automatic backups are off', (t) => {
+  const root = makeTmpDir('auto-backup-off');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'G' });
+  const s = { get: () => ({ automatic: false, everyNSaves: 1 }) };
+  assert.equal(autoSnapshotIfDue(store, guide.guideId, s), null);
+  assert.equal(autoSnapshotIfDue(store, guide.guideId, s), null);
+  const dir = path.join(store.guideDir(guide.guideId), 'history', 'snapshots');
+  assert.equal(fs.existsSync(dir) ? fs.readdirSync(dir).length : 0, 0);
+});

tests/unit/store-revisions.test.js

@@ -0,0 +1,143 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const { GuideStore, RevisionConflictError } = require('../../core/store');
+const { makeTmpDir, rmrf, TINY_PNG } = require('./helpers');
+
+// ---- revisions --------------------------------------------------------------
+
+test('revisions start at 0 and increment on every save', (t) => {
+  const root = makeTmpDir('store-rev');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+
+  const guide = store.createGuide({ title: 'G' });
+  assert.equal(guide.revision, 0);
+
+  const step = store.addStep(guide.guideId, { title: 'S' }, TINY_PNG, { width: 1, height: 1 });
+  const r0 = store.getStep(guide.guideId, step.stepId).revision;
+
+  const saved1 = store.saveStep(guide.guideId, { ...step, title: 'S1' });
+  assert.equal(saved1.revision, r0 + 1);
+  const saved2 = store.saveStep(guide.guideId, { ...saved1, title: 'S2' });
+  assert.equal(saved2.revision, r0 + 2);
+});
+
+test('compare-and-swap: a stale expectedRevision is rejected, not clobbered', (t) => {
+  const root = makeTmpDir('store-cas');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'G' });
+  const step = store.addStep(guide.guideId, { title: 'S' }, TINY_PNG, { width: 1, height: 1 });
+
+  const base = store.getStep(guide.guideId, step.stepId);
+  // A user edit lands first (no expectedRevision -> last-write-wins).
+  store.saveStep(guide.guideId, { ...base, title: 'user edit' });
+
+  // A background writer that read `base` tries to save with the stale revision.
+  assert.throws(
+    () => store.saveStep(guide.guideId, { ...base, title: 'stale background' }, { expectedRevision: base.revision }),
+    (err) => err instanceof RevisionConflictError && err.code === 'STEPFORGE_REVISION_CONFLICT'
+  );
+  // The user edit survived.
+  assert.equal(store.getStep(guide.guideId, step.stepId).title, 'user edit');
+});
+
+test('compare-and-swap succeeds when the revision still matches', (t) => {
+  const root = makeTmpDir('store-cas-ok');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'G' });
+  const step = store.addStep(guide.guideId, { title: 'S' }, TINY_PNG, { width: 1, height: 1 });
+  const base = store.getStep(guide.guideId, step.stepId);
+
+  const saved = store.saveStep(guide.guideId, { ...base, title: 'ok' }, { expectedRevision: base.revision });
+  assert.equal(saved.title, 'ok');
+  assert.equal(saved.revision, base.revision + 1);
+});
+
+test('guide saves are revision-aware too', (t) => {
+  const root = makeTmpDir('store-guide-cas');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'G' });
+  const base = store.getGuide(guide.guideId);
+  store.saveGuide({ ...base, title: 'first' });
+  assert.throws(
+    () => store.saveGuide({ ...base, title: 'stale' }, { expectedRevision: base.revision }),
+    RevisionConflictError
+  );
+});
+
+test('v1 data without a revision field reads as revision 0 and upgrades on save', (t) => {
+  const root = makeTmpDir('store-v1');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'G' });
+
+  // Simulate legacy on-disk data: strip the revision field.
+  const file = path.join(store.guidesDir, guide.guideId, 'guide.json');
+  const raw = JSON.parse(fs.readFileSync(file, 'utf8'));
+  delete raw.revision;
+  fs.writeFileSync(file, JSON.stringify(raw));
+
+  const loaded = store.getGuide(guide.guideId);
+  assert.equal(loaded.revision, 0);
+  const saved = store.saveGuide(loaded);
+  assert.equal(saved.revision, 1);
+});
+
+// ---- corruption quarantine --------------------------------------------------
+
+test('a corrupt guide is quarantined and reported, not silently dropped', (t) => {
+  const root = makeTmpDir('store-quarantine-guide');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const good = store.createGuide({ title: 'Good' });
+  const bad = store.createGuide({ title: 'Bad' });
+
+  // Corrupt the bad guide's JSON.
+  fs.writeFileSync(path.join(store.guidesDir, bad.guideId, 'guide.json'), '{ not valid json');
+
+  const listed = store.listGuides();
+  assert.deepEqual(listed.map((g) => g.guideId), [good.guideId]);
+
+  const report = store.getRecoveryReport();
+  assert.equal(report.length, 1);
+  assert.equal(report[0].kind, 'guide');
+  // The original bytes are preserved in quarantine, not deleted.
+  assert.ok(fs.existsSync(report[0].quarantined));
+  // The bad guide dir is gone from the live library.
+  assert.equal(fs.existsSync(path.join(store.guidesDir, bad.guideId)), false);
+});
+
+test('a corrupt step is quarantined and reported', (t) => {
+  const root = makeTmpDir('store-quarantine-step');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  const guide = store.createGuide({ title: 'G' });
+  const good = store.addStep(guide.guideId, { title: 'good' }, TINY_PNG, { width: 1, height: 1 });
+  const bad = store.addStep(guide.guideId, { title: 'bad' }, TINY_PNG, { width: 1, height: 1 });
+
+  fs.writeFileSync(path.join(store.stepDir(guide.guideId, bad.stepId), 'step.json'), 'nonsense');
+
+  const steps = store.listSteps(guide.guideId);
+  assert.ok(steps.has(good.stepId));
+  assert.equal(steps.has(bad.stepId), false);
+  const report = store.getRecoveryReport();
+  assert.equal(report.some((r) => r.kind === 'step'), true);
+});
+
+test('an empty/in-progress guide directory is not treated as corruption', (t) => {
+  const root = makeTmpDir('store-empty-dir');
+  t.after(() => rmrf(root));
+  const store = new GuideStore(root);
+  // A directory with no guide.json (e.g. mid-create) must be skipped quietly.
+  fs.mkdirSync(path.join(store.guidesDir, 'orphan-dir'), { recursive: true });
+  assert.doesNotThrow(() => store.listGuides());
+  assert.equal(store.getRecoveryReport().length, 0);
+});