fix: flutter analyze Warnings beheben (totes/unerreichbares Code)

Entfernt tatsächlich toten Code, den flutter analyze als Warning markiert
hatte: unbenutzte Felder/Parameter (_saved, _hovered wird jetzt für Hover-
Feedback genutzt, destructive-Flag ohne Aufrufer, size-Parameter ohne
Override), unerreichbaren dead_code (Room.topic/Space.topic sind laut SDK
nie null, client.database ist nie null) sowie Legacy-Funktionen aus der
alten Push-Architektur (_showNotif/_fetchTitle, ersetzt durch natives
PushService.kt) und einen leeren Noise-Suppression-Stub ohne Aufrufer.
Keine funktionale Verhaltensänderung an aktiven Code-Pfaden.

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

lib/core/background_push.dart

@@ -1,6 +1,4 @@
-import 'dart:convert';
 import 'dart:io';
-import 'dart:isolate';
 import 'dart:ui';
 
 import 'package:firebase_messaging/firebase_messaging.dart';
@@ -14,8 +12,6 @@ import 'package:path_provider/path_provider.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'package:sqflite/sqflite.dart' as sqflite_native;
 
-const _kChannel = 'pyramid_messages';
-
 /// Port name used to locate the main isolate from background isolates.
 /// Registered by notification_service.dart when the app starts.
 const kMainIsolateName = 'pyramid_main';
@@ -304,99 +300,3 @@ Future<void> handleBackgroundNotificationResponse(
   print('[NOTIF-BG] background reply sent=$sent room=$roomId');
 }
 
-// ── Notification builder ──────────────────────────────────────────────────────
-
-Future<void> _showNotif({
-  required String  title,
-  required String  body,
-  required String? roomId,
-  required int     notifId,
-}) async {
-  final plugin = FlutterLocalNotificationsPlugin();
-  await plugin.initialize(
-    const InitializationSettings(
-        android: AndroidInitializationSettings('@drawable/ic_notification')),
-    onDidReceiveBackgroundNotificationResponse: handleBackgroundNotificationResponse,
-  );
-
-  await plugin.show(
-    notifId, title, body,
-    NotificationDetails(
-      android: AndroidNotificationDetails(
-        _kChannel, 'Nachrichten',
-        channelDescription: 'Neue Nachrichten',
-        importance: Importance.high,
-        priority:   Priority.high,
-        icon:       '@drawable/ic_notification',
-        color:      const Color(0xFF7B61FF),
-        groupKey:   'pyramid_messages',
-        actions: roomId != null
-            ? const [
-                AndroidNotificationAction(
-                  'reply', 'Antworten',
-                  inputs: [AndroidNotificationActionInput(label: 'Antworten…')],
-                  allowGeneratedReplies: true,
-                  showsUserInterface: false, // BroadcastReceiver path — app never opens
-                ),
-                AndroidNotificationAction(
-                  'read', 'Gelesen',
-                  showsUserInterface: false,
-                ),
-              ]
-            : const [],
-      ),
-    ),
-    payload: roomId,
-  );
-}
-
-// ── HTTP fallback — fetch sender / room name without the SDK ──────────────────
-
-Future<String?> _fetchTitle(
-    String hs, String token, String roomId, String eventId) async {
-  try {
-    final encRoom  = Uri.encodeComponent(roomId);
-    final encEvent = Uri.encodeComponent(eventId);
-
-    final rawEvent = await _get(
-        '$hs/_matrix/client/v3/rooms/$encRoom/event/$encEvent', token);
-    if (rawEvent == null) return null;
-
-    final senderId = rawEvent['sender'] as String? ?? '';
-    String senderName = senderId.split(':').first.replaceFirst('@', '');
-
-    if (senderId.isNotEmpty) {
-      final encSender = Uri.encodeComponent(senderId);
-      final memberState = await _get(
-          '$hs/_matrix/client/v3/rooms/$encRoom/state/m.room.member/$encSender',
-          token);
-      final name = memberState?['displayname'] as String?;
-      if (name != null && name.isNotEmpty) senderName = name;
-    }
-
-    final nameState =
-        await _get('$hs/_matrix/client/v3/rooms/$encRoom/state/m.room.name', token);
-    final roomName = nameState?['name'] as String?;
-
-    return roomName?.isNotEmpty == true
-        ? '$senderName · $roomName'
-        : senderName;
-  } catch (_) {
-    return null;
-  }
-}
-
-Future<Map<String, dynamic>?> _get(String url, String token) async {
-  try {
-    final req = await HttpClient()
-        .getUrl(Uri.parse(url))
-        .timeout(const Duration(seconds: 8));
-    req.headers.add('Authorization', 'Bearer $token');
-    final res = await req.close();
-    if (res.statusCode != 200) return null;
-    final raw = await res.transform(utf8.decoder).join();
-    return jsonDecode(raw) as Map<String, dynamic>;
-  } catch (_) {
-    return null;
-  }
-}

lib/core/livekit_call_manager.dart

@@ -586,8 +586,6 @@ class LiveKitCallManager with ChangeNotifier {
     }
   }
 
-  void _applyNoiseSuppression(bool enabled) {}
-
   void _startStatsLogging() {
     _stopStatsLogging();
     _statsTimer = Timer.periodic(const Duration(seconds: 5), (_) => _logStats());