feat(chat): implement room synchronization for adult-only mode in MultiChatDialog.vue

- Added logic to handle room synchronization when entering a chat in adult-only mode.
- Introduced a flag to manage ongoing room sync requests, improving user experience during room transitions.

frontend/src/dialogues/chat/MultiChatDialog.vue

@@ -363,6 +363,7 @@ export default {
             heartbeatIntervalMs: 30000, // 30 seconds
             connectAttemptTimeout: null,
             joinFallbackTimer: null,
+            roomSyncInFlight: false,
             // Faster handshake watchdog separate from reconnect interval
             handshakeWatchdogMs: 2500,
             // Rotate to next candidate if a connection never reaches 'open'
@@ -1176,9 +1177,25 @@ export default {
                     this.setStatus('connected');
                     if (this.connectAttemptTimeout) { clearTimeout(this.connectAttemptTimeout); this.connectAttemptTimeout = null; }
                     if (this.joinFallbackTimer) { clearTimeout(this.joinFallbackTimer); this.joinFallbackTimer = null; }
+                    const actualRoom = msg.to || msg.room || msg.roomName || '';
+                    const desiredRoom = this.resolveInitialRoomName();
+                    if (
+                        this.adultOnlyMode
+                        && desiredRoom
+                        && actualRoom
+                        && desiredRoom !== actualRoom
+                        && !this.roomSyncInFlight
+                    ) {
+                        this.roomSyncInFlight = true;
+                        this.sendWithToken({ type: 'join', room: desiredRoom, password: this.getRoomPassword(desiredRoom) });
+                        window.setTimeout(() => {
+                            this.roomSyncInFlight = false;
+                        }, 1000);
+                        return;
+                    }
                     // Eigene Beitrittsmeldung einmalig mit Raumname anzeigen
                     if (!this.announcedRoomEnter) {
-                        const room = msg.to || msg.room || msg.roomName || this.getSelectedRoomName();
+                        const room = actualRoom || this.getSelectedRoomName();
                         if (room) {
                             const text = this.$t('chat.multichat.system.room_entered', { room });
                             this.messages.push({ id: msg.id || Date.now(), user: 'System', text });