feat: Phase 2 complete — calls, media, spaces, persistence, chat improvements

- LiveKit/MatrixRTC voice+video calls with full call screen UI
- Incoming call overlay (accept/decline)
- Media upload/download — file picker, image rendering, file download
- Spaces navigation — space list + expandable child rooms
- Drift persistence — rooms + messages written on every sync
- Sync persistence auto-starts on login and session restore
- Chat: typing indicators, long-press menu, reply, emoji reactions
- User search dialog + start DM from rooms screen
- Android: INTERNET + CAMERA + RECORD_AUDIO permissions in main manifest
- Emoji picker for reactions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/features/rooms/presentation/rooms_screen.dart

@@ -1,4 +1,4 @@
-// Version: 1.0.0 | Created: 2026-04-01
+// Version: 1.1.0 | Created: 2026-04-01
 // Main rooms list screen with bottom navigation.
 
 import 'package:flutter/material.dart';
@@ -9,6 +9,7 @@ import '../../profile/presentation/profile_screen.dart';
 import '../../spaces/presentation/spaces_screen.dart';
 import 'room_tile.dart';
 import 'rooms_controller.dart';
+import 'user_search_dialog.dart';
 
 class RoomsScreen extends ConsumerStatefulWidget {
   const RoomsScreen({super.key});
@@ -64,9 +65,7 @@ class _RoomsScreenState extends ConsumerState<RoomsScreen> {
                 IconButton(
                   icon: const Icon(Icons.edit_square),
                   tooltip: 'New message',
-                  onPressed: () {
-                    // Phase 2: start a new DM or group chat
-                  },
+                  onPressed: () => showUserSearchDialog(context),
                 ),
               ],
             )