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>

web/protocol/web-preferences.ts

@@ -84,7 +84,7 @@ export const DEFAULT_WEB_PREFERENCES: WebPreferencesIR = {
   schemaVersion: WEB_PREFERENCES_SCHEMA_VERSION,
   interface: {
     showStatus: true,
-    quickTools: false,
+    quickTools: true,
     showAreaSwitcher: true,
     showObjectInfo: true,
     showViewName: true,