fix(offline): report editor-warm failures honestly; cover failure labels; align docs (F1-F3)

F1: warmPageYdoc now returns didSync (true only on the real 'synced' event,
    false on the 8s timeout / error, which are now logged). The tree menu gates
    the 'available offline' success toast on result.ok AND didSync, and pushes
    'editor' into the failed set otherwise — so a page whose Yjs body never
    warmed is no longer reported as fully offline-available.
F2: tests for the page/space/currentUser failure labels and the didSync
    true/false paths.
F3: correct the mobile-app-plan / mobile-bootstrap present-state sections to
    match shipped code (Capacitor, CORS allowlist, Swagger, offline reading,
    /l in the SW denylist).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/mobile-bootstrap.md

@@ -15,8 +15,10 @@ mobile app for Gitmost, per the first-step checklist in
   `main.tsx` and skipped inside the Capacitor native WebView. The SW precaches the
   app shell (`globPatterns` js/css/html/...) and serves `navigateFallback:
   "index.html"` for SPA routes, with `navigateFallbackDenylist` excluding the
-  server-owned routes `/api`, `/collab`, `/socket.io`, `/share/`, `/mcp`, and
-  `/robots.txt`. `runtimeCaching` keeps `/collab`, `/socket.io`, and all `/api`
+  server-owned routes `/api`, `/collab`, `/socket.io`, `/share/`, `/mcp`, `/l`
+  (the vanity short-link `l/:alias`, excluded from the `/api` global prefix and
+  resolved server-side), and `/robots.txt`. `runtimeCaching` keeps `/collab`,
+  `/socket.io`, and all `/api`
   as `NetworkOnly` — offline reads are served by the persisted TanStack Query
   cache (IndexedDB) and `y-indexeddb` for the page Yjs doc, not by an SW HTTP
   cache. This lets the existing responsive web UI be installed and run as a