Fix export block ordering, stale per-step UI, and cross-step block loss

Exporters now interleave text/code/table blocks in the same order they
appear in the editor's Blocks panel (via a shared stepContentGroups
helper) instead of grouping by kind, so exported docs match the guide
editor's ordering.

selectStep() now also refreshes the Focused View controls and Blocks
panel (previously only done by renderAll), so switching steps no longer
leaves the previous step's blocks/focused-view sliders on screen. It
also flushes any pending edits on the outgoing step before switching, so
a later guide-wide reload (e.g. applying an annotation style to the
whole guide) can't discard unsaved text-block edits on other steps.

exporters/pdf.js

@@ -3,7 +3,7 @@
 const fs = require('node:fs');
 const path = require('node:path');
 const { PdfBuilder } = require('../core/pdf');
-const { guideSlug, renderAllImages, LEVEL_LABEL, stepBlocks, codeBlockText } = require('./common');
+const { guideSlug, renderAllImages, LEVEL_LABEL, stepContentGroups, codeBlockText } = require('./common');
 const { htmlToText } = require('../core/util');
 const { htmlToBlocks } = require('../core/htmlblocks');
 
@@ -207,7 +207,8 @@ function exportPdf(ast, outDir, template = {}) {
     pdf.rect(M, y, usableW, 0.8, { fill: [225, 228, 232] });
     y += 8;
 
-    emitBlocks(step, 'before-description');
+    const { before, rest } = stepContentGroups(step);
+    for (const tb of before) emitBlock(tb);
     if (step.descriptionHtml) writeDescription(step.descriptionHtml);
 
     const img = images.get(step.stepId);
@@ -221,8 +222,10 @@ function exportPdf(ast, outDir, template = {}) {
       y += h + 10;
     }
 
-    for (const block of stepBlocks(step).filter((item) => item.kind !== 'text')) {
-      if (block.kind === 'code') {
+    for (const block of rest) {
+      if (block.kind === 'text') {
+        emitBlock(block);
+      } else if (block.kind === 'code') {
         const lines = String(codeBlockText(block) || '').split('\n');
         const lineH = 9 * 1.3;
         ensure(Math.min(lines.length, 4) * lineH + 12);
@@ -255,45 +258,41 @@ function exportPdf(ast, outDir, template = {}) {
       }
     }
 
-    emitBlocks(step, 'after-description');
-    emitBlocks(step, 'after-image');
     y += 10;
   }
 
-  function emitBlocks(step, position) {
-    for (const tb of stepBlocks(step).filter((b) => b.kind === 'text' && b.position === position)) {
-      const label = `${LEVEL_LABEL[tb.level] || 'Note'}${tb.title ? `: ${tb.title}` : ''}`;
-      const { items, height: bodyH } = tb.descriptionHtml
-        ? layoutDescription(pdf, tb.descriptionHtml, usableW - 18, 9.5)
-        : { items: [], height: 0 };
-      const blockH = 16 + bodyH;
-      const style = LEVEL_STYLE[tb.level] || LEVEL_STYLE.info;
-      ensure(blockH + 4);
-      pdf.rect(M, y, usableW, blockH, { fill: style.tint });
-      pdf.rect(M, y, 3, blockH, { fill: style.accent });
-      pdf.text(label, M + 10, y + 2, { size: 9.5, font: 'F2', color: style.accent });
-      let by = y + 16;
-      for (const item of items) {
-        if (item.kind === 'hr') {
-          pdf.rect(M + 10, by + 5, item.width, 0.8, { fill: [225, 228, 232] });
-          by += 12;
-          continue;
-        }
-        item.lines.forEach((line, idx) => {
-          const textX = M + 10 + item.indent;
-          if (idx === 0 && item.prefix) pdf.text(item.prefix, textX - LIST_INDENT, by, { size: item.size, font: 'F1' });
-          const parts = line.map((word) => ({
-            text: word.text,
-            font: word.font,
-            color: word.href ? tpl.accentColor : (item.muted ? [100, 100, 100] : [0, 0, 0]),
-          }));
-          pdf.textRun(parts, textX, by, item.size);
-          by += item.lineHeight;
-        });
-        by += 4;
+  function emitBlock(tb) {
+    const label = `${LEVEL_LABEL[tb.level] || 'Note'}${tb.title ? `: ${tb.title}` : ''}`;
+    const { items, height: bodyH } = tb.descriptionHtml
+      ? layoutDescription(pdf, tb.descriptionHtml, usableW - 18, 9.5)
+      : { items: [], height: 0 };
+    const blockH = 16 + bodyH;
+    const style = LEVEL_STYLE[tb.level] || LEVEL_STYLE.info;
+    ensure(blockH + 4);
+    pdf.rect(M, y, usableW, blockH, { fill: style.tint });
+    pdf.rect(M, y, 3, blockH, { fill: style.accent });
+    pdf.text(label, M + 10, y + 2, { size: 9.5, font: 'F2', color: style.accent });
+    let by = y + 16;
+    for (const item of items) {
+      if (item.kind === 'hr') {
+        pdf.rect(M + 10, by + 5, item.width, 0.8, { fill: [225, 228, 232] });
+        by += 12;
+        continue;
       }
-      y += blockH + 6;
+      item.lines.forEach((line, idx) => {
+        const textX = M + 10 + item.indent;
+        if (idx === 0 && item.prefix) pdf.text(item.prefix, textX - LIST_INDENT, by, { size: item.size, font: 'F1' });
+        const parts = line.map((word) => ({
+          text: word.text,
+          font: word.font,
+          color: word.href ? tpl.accentColor : (item.muted ? [100, 100, 100] : [0, 0, 0]),
+        }));
+        pdf.textRun(parts, textX, by, item.size);
+        by += item.lineHeight;
+      });
+      by += 4;
     }
+    y += blockH + 6;
   }
 
   fs.mkdirSync(outDir, { recursive: true });