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/spaces/data/spaces_repository.dart

@@ -0,0 +1,71 @@
+// Version: 1.1.0 | Created: 2026-04-01
+// SpacesRepository — builds space list and child rooms from the Matrix SDK.
+// A space is a room where isSpace == true.
+
+import 'package:matrix/matrix.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+import '../../../core/network/matrix_client.dart';
+import '../domain/space_model.dart';
+
+part 'spaces_repository.g.dart';
+
+@riverpod
+SpacesRepository spacesRepository(Ref ref) {
+  return SpacesRepository(client: ref.watch(matrixClientProvider));
+}
+
+class SpacesRepository {
+  SpacesRepository({required Client client}) : _client = client;
+
+  final Client _client;
+
+  /// Returns all rooms that are spaces.
+  List<SpaceModel> getSpaces() {
+    return _client.rooms.where((r) => r.isSpace).map(_toSpaceModel).toList();
+  }
+
+  /// Returns child rooms within [spaceId] that the client is a member of.
+  ///
+  /// SpaceChild gives us the roomId only. We look up the Room from the client
+  /// to get display name and avatar. If the child room is not in the client's
+  /// room list (not joined), it is omitted.
+  List<SpaceRoomModel> getRoomsInSpace(String spaceId) {
+    final space = _client.getRoomById(spaceId);
+    if (space == null || !space.isSpace) return [];
+
+    final result = <SpaceRoomModel>[];
+    for (final child in space.spaceChildren) {
+      final childRoomId = child.roomId;
+      if (childRoomId == null) continue;
+
+      final room = _client.getRoomById(childRoomId);
+      if (room == null) continue; // not joined — skip
+
+      result.add(
+        SpaceRoomModel(
+          id: room.id,
+          displayName: room.getLocalizedDisplayname(),
+          avatarUrl: room.avatar?.toString(),
+          isDirect: room.isDirectChat,
+        ),
+      );
+    }
+    return result;
+  }
+
+  /// Stream that emits on every sync so the UI stays current.
+  Stream<List<SpaceModel>> watchSpaces() async* {
+    yield getSpaces();
+    yield* _client.onSync.stream.map((_) => getSpaces());
+  }
+
+  SpaceModel _toSpaceModel(Room room) {
+    return SpaceModel(
+      id: room.id,
+      displayName: room.getLocalizedDisplayname(),
+      avatarUrl: room.avatar?.toString(),
+      roomCount: room.spaceChildren.length,
+    );
+  }
+}