feat(manual): add the illustrated Web Blender HTML user manual

A single-page 28-chapter manual generated from manual.json covers the
11 workspaces, all React editors, OPFS save/reopen, explicit local
downloads, import/export routes, preferences/keymap and the capability
matrix. It reuses verified course screenshots and adds 14 fresh
Chromium captures for shell, storage, area, camera, preferences, IO and
troubleshooting chapters.

Manual-driven fixes: Save As now states OPFS-only, GLTF import is
restored, quick toolbar honors its preference, startup workspace is
applied, Properties tabs jump to sections, Outliner fallback search
filters, and the editor-header ⋮ opens the area menu. Help and the
tutorial landing link the new manual; the PDF remains as an archive.

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

tests/golden/USER-MANUAL-001/capture-report.json

@@ -0,0 +1,65 @@
+{
+  "schemaVersion": 1,
+  "status": "PASS",
+  "generatedAt": "2026-11-13T03:55:08.851Z",
+  "gpuMode": "hardware",
+  "images": [
+    {
+      "name": "ch01-first-save",
+      "file": "web/app/public/manuals/images/ch01-first-save.jpg"
+    },
+    {
+      "name": "ch03-recent",
+      "file": "web/app/public/manuals/images/ch03-recent.jpg"
+    },
+    {
+      "name": "ch05-recovery",
+      "file": "web/app/public/manuals/images/ch05-recovery.jpg"
+    },
+    {
+      "name": "ch06-area-menu",
+      "file": "web/app/public/manuals/images/ch06-area-menu.jpg"
+    },
+    {
+      "name": "ch06-area-split",
+      "file": "web/app/public/manuals/images/ch06-area-split.jpg"
+    },
+    {
+      "name": "ch07-camera-view",
+      "file": "web/app/public/manuals/images/ch07-camera-view.jpg"
+    },
+    {
+      "name": "ch08-outliner",
+      "file": "web/app/public/manuals/images/ch08-outliner.jpg"
+    },
+    {
+      "name": "ch09-properties-tabs",
+      "file": "web/app/public/manuals/images/ch09-properties-tabs.jpg"
+    },
+    {
+      "name": "ch21-physics",
+      "file": "web/app/public/manuals/images/ch21-physics.jpg"
+    },
+    {
+      "name": "ch25-import-menu",
+      "file": "web/app/public/manuals/images/ch25-import-menu.jpg"
+    },
+    {
+      "name": "ch25-export-menu",
+      "file": "web/app/public/manuals/images/ch25-export-menu.jpg"
+    },
+    {
+      "name": "ch27-preferences",
+      "file": "web/app/public/manuals/images/ch27-preferences.jpg"
+    },
+    {
+      "name": "ch27-keymap",
+      "file": "web/app/public/manuals/images/ch27-keymap.jpg"
+    },
+    {
+      "name": "ch28-help",
+      "file": "web/app/public/manuals/images/ch28-help.jpg"
+    }
+  ],
+  "failures": []
+}

tests/golden/USER-MANUAL-001/check-report.json

@@ -0,0 +1,9 @@
+{
+  "schemaVersion": 1,
+  "status": "PASS",
+  "chapters": 28,
+  "parts": 6,
+  "capabilities": 31,
+  "gaps": 7,
+  "errors": []
+}