docs: Wahl result view, live chat, and the gateway race fix

Plan + client README updated for the guest Wahl result endpoint/tab, the
WebSocket chat wiring, and the ChatGateway caller-promise fix. Section 8
now scopes the remaining Flutter work to the Authentik-dependent screens.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

client/app/README.md

@@ -26,13 +26,15 @@ backend, which also serves the interim plain-HTML client at `/`).
 - The token is stored via `shared_preferences` (localStorage on web) and
   restored on start; `GET /auth/me` resolves the role for a role-aware home.
 - **Home** (`lib/screens/home_screen.dart`) — identity card + navigation.
-- **Workshop-Wahl** (`lib/screens/wahl_screen.dart`, guests) — loads
-  `GET /wahl/guest/overview`, tap workshops in order (max 3) to set
-  priorities, `POST /wahl/:id/teilnehmer`.
+- **Workshop-Wahl** (`lib/screens/wahl_screen.dart`, guests) — two tabs:
+  *Wünsche* (`GET /wahl/guest/overview`, tap workshops in order, max 3,
+  `POST /wahl/:id/teilnehmer`) and *Ergebnis* (`GET /wahl/guest/results` —
+  PENDING / ASSIGNED with workshop + wish rank / UNASSIGNED).
 - **Dateien** (`lib/screens/files_screen.dart`) — `GET /files/:kcId`,
   filtered server-side by the caller's visibility tier.
-- **Chat** (`lib/screens/chat_screen.dart`) — channel + message list
-  (read-only; sending is a WebSocket path, still to do).
+- **Chat** (`lib/screens/chat_screen.dart` + `lib/chat_socket.dart`) —
+  channel list, REST history, then a live `/chat` WebSocket connection
+  (`chat:join` / `chat:send` / `chat:message`) with a compose bar.
 
 ## Architecture