docs(ui): sync docs to the app-shell; fix stale nav comments

Rewrite ui/docs (navigation, order-composer, auth-flow, pwa-strategy,
game-state + secondary topic docs) and ui/README for the single-URL
app-shell (in-memory screens/views, Back→lobby via shallow routing,
sessionStorage restore + validation, return-to-lobby). ui/PLAN.md gets a
Phase-10 supersede note (implemented; standalone-compatible). Fix stale
code comments (session-store auth gate, report-sections spec contract).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/docs/storage.md

@@ -186,7 +186,8 @@ Thin orchestration layer over `KeyStore` + `Cache`:
   push-event-driven revocation path.
 
 A `null` `deviceSessionId` is the signal that the session is
-unauthenticated — the root layout routes such users to `/login`.
+unauthenticated — `session.status` settles to `anonymous` and the
+dispatcher renders the login screen (the app-shell stays at `/game/`).
 
 ## Test layout