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/lib/api.dart

@@ -326,7 +326,7 @@ class Api {
     );
   }
 
-  // --- chat (read-only for now; sending is a WebSocket-only path) ---
+  // --- chat: REST for channels/history; live send/receive is the /chat WS ---
   Future<List<ChatChannel>> channels(String kcId) async {
     final list = await _get('/chat/$kcId/channels') as List<dynamic>;
     return list.map((e) => ChatChannel.fromJson(e as Map<String, dynamic>)).toList();