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/frontend/src/lib/session-store.svelte.ts

@@ -16,8 +16,8 @@
 // asynchronously; the watcher in `lib/revocation-watcher.ts` calls
 // it without user interaction. The post-condition is the same as
 // `signOut("user")` — keypair regenerated, session id wiped,
-// status returned to `anonymous` — so the layout's existing
-// `anonymous → /login` redirect handles both reasons uniformly.
+// status returned to `anonymous` — so the dispatcher's state-based
+// auth gate renders the login screen for both reasons uniformly.
 
 import type {
 	Cache,
@@ -83,7 +83,7 @@ export class SessionStore {
 	 * revoked public key, and returns the status to `anonymous`. The
 	 * `reason` is recorded in console output for telemetry but does
 	 * not change the post-state — both user-driven logout and
-	 * gateway-driven revocation land the user back on `/login`.
+	 * gateway-driven revocation return the user to the login screen.
 	 */
 	async signOut(reason: "user" | "revoked"): Promise<void> {
 		if (this.keyStore === null || this.cache === null) {