feat: cartões de publicação em canais e corrreções de salas arquivadas

- Canais: publicações viram cartões de largura total mantendo todas as
  funções do balão (reações, resposta, editar, excluir, comentários em
  thread). Composer de publicação fica restrito a admins no feed; membros
  comentam via tela de thread. Canais novos usam events_default 0 para
  permitir comentários e reações.
- Ao sair/excluir uma sala, a cópia local é removida do banco imediatamente;
  salas já deixadas no servidor não apresentam mais erro ao excluir de novo.
- Classificação mural/canal carregada direto do sync (room_type em
  importantStateEvents + postLoad) sem precisar abrir a sala.
- Diálogos com raio e padding reduzidos (dialogTheme, text input e ok/cancel).
- Ícones do app regenerados (logo_background) e dependência linkify.

lib/pages/chat_list/chat_list.dart

@@ -14,6 +14,7 @@ import 'package:tatchat/pages/chat_list/tabs/home_tab.dart';
 import 'package:tatchat/utils/error_reporter.dart';
 import 'package:tatchat/utils/localized_exception_extension.dart';
 import 'package:tatchat/utils/matrix_sdk_extensions/matrix_locals.dart';
+import 'package:tatchat/utils/matrix_sdk_extensions/room_extension.dart';
 import 'package:tatchat/utils/platform_infos.dart';
 import 'package:tatchat/utils/show_scaffold_dialog.dart';
 import 'package:tatchat/utils/show_update_snackbar.dart';
@@ -402,6 +403,7 @@ class ChatListController extends State<ChatList>
   }
 
   StreamSubscription? _onRoomTagUpdate;
+  StreamSubscription? _backfillSubscription;
 
   @override
   void initState() {
@@ -411,6 +413,8 @@ class ChatListController extends State<ChatList>
 
     scrollController.addListener(_onScroll);
     _waitForFirstSync();
+    _backfillSubscription =
+        _clientStream.stream.listen((_) => backfillRoomTypeMarkers());
     if (PlatformInfos.isMobile) {
       _callEventSubscription = FlutterCallkitIncoming.onEvent.listen(
         _onCallEvent,
@@ -474,6 +478,7 @@ class ChatListController extends State<ChatList>
     _intentFileStreamSubscription?.cancel();
     _callEventSubscription?.cancel();
     _onRoomTagUpdate?.cancel();
+    _backfillSubscription?.cancel();
     scrollController.removeListener(_onScroll);
     searchController.dispose();
     searchFocusNode.dispose();
@@ -775,7 +780,10 @@ class ChatListController extends State<ChatList>
         if (confirmed == OkCancelResult.cancel) return;
         if (!mounted) return;
 
-        await showFutureLoadingDialog(context: context, future: room.leave);
+        await showFutureLoadingDialog(
+          context: context,
+          future: () => leaveRoom(room),
+        );
 
         return;
       case ChatContextAction.addToSpace:
@@ -901,6 +909,65 @@ class ChatListController extends State<ChatList>
 
   bool waitForFirstSync = false;
 
+  /// Leaves the room locally and removes it from the local database.
+  Future<void> leaveRoom(Room room) async {
+    try {
+      await room.leave();
+    } on MatrixException catch (e, s) {
+      // If the room was already left on the server (e.g. a stale local copy
+      // reappeared after a restart) the leave request fails, but the user
+      // intent (room not being listed anymore) is already fulfilled. Clean up
+      // locally instead of showing an error.
+      if (!{
+        MatrixError.M_FORBIDDEN,
+        MatrixError.M_NOT_FOUND,
+        MatrixError.M_UNKNOWN,
+      }.contains(e.error)) {
+        Logs().w('Failed to leave room ${room.id}', e, s);
+        rethrow;
+      }
+      Logs().w('Room ${room.id} is already gone, cleaning up locally...', e, s);
+    }
+    final client = room.client;
+    // Make sure the room does not reappear from the local database after an
+    // app restart, even if the leave sync did not run in time.
+    await client.database.forgetRoom(room.id);
+    client.rooms.remove(room);
+  }
+
+  /// Loads the shared [roomTypeStateEvent] marker from the synced room state
+  /// (from the local database for partially loaded rooms) and writes it for
+  /// existing canal/mural rooms that only have the per-account tag of the
+  /// creating account. This makes the category visible right after the sync,
+  /// without having to open the room first. Only admins can write the marker,
+  /// non-admin members simply read it.
+  Future<void> backfillRoomTypeMarkers() async {
+    final client = Matrix.of(context).client;
+    if (client.rooms.isEmpty) return;
+    for (final room in client.rooms) {
+      if (room.membership != Membership.join) continue;
+      if (room.roomType != null) continue;
+      // Partial rooms do not keep unimportant state events (like our room type
+      // marker) in memory, so load them from the local database first.
+      await room.postLoad();
+      final type =
+          room.roomType ??
+          (room.tags.keys.contains(AppConfig.canalTag)
+              ? 'canal'
+              : room.tags.keys.contains(AppConfig.muralTag)
+              ? 'mural'
+              : null);
+      if (type == null || room.roomType == type) continue;
+      if (room.ownPowerLevel < PowerLevel.admin) continue;
+      try {
+        await room.setRoomType(type);
+      } catch (e, s) {
+        Logs().w('Failed to backfill room type $type for ${room.id}', e, s);
+      }
+    }
+    if (mounted) setState(() {});
+  }
+
   Future<void> _waitForFirstSync() async {
     final router = GoRouter.of(context);
     final client = Matrix.of(context).client;
@@ -921,6 +988,7 @@ class ChatListController extends State<ChatList>
     setState(() {
       waitForFirstSync = true;
     });
+    backfillRoomTypeMarkers();
 
     if (client.userDeviceKeys[client.userID!]?.deviceKeys.values.any(
           (device) => !device.verified && !device.blocked,