Scaffold StepForge: docs, license, audit, npm project

- Environment audit and stack decision in build/agent_audit.md
  (Node + Electron shell over dependency-free core; deviation recorded)
- Rewrite README/ARCHITECTURE/CONTRIBUTING for StepForge
- Add SECURITY.md threat model, CODE_OF_CONDUCT.md, CHANGELOG.md, MPL-2.0
- Replace template grep checks with structural workflow check

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

package.json

@@ -0,0 +1,17 @@
+{
+  "name": "stepforge",
+  "version": "0.1.0",
+  "description": "Fully offline desktop tool for capturing, annotating, and exporting step-by-step guides.",
+  "main": "app/main.js",
+  "license": "MPL-2.0",
+  "private": true,
+  "scripts": {
+    "start": "electron .",
+    "test": "node --test tests/unit/",
+    "verify": "bash scripts/verify.sh",
+    "sample": "node scripts/make-sample-guide.js"
+  },
+  "devDependencies": {
+    "electron": "^41.7.1"
+  }
+}