fix(chat): improve room announcement logic in MultiChatDialog.vue

- Enhanced the logic for announcing room entries, particularly in adult-only mode, to ensure accurate messaging based on room selection.
- Added checks to prevent redundant announcements and ensure proper synchronization with the selected room.

frontend/src/dialogues/chat/MultiChatDialog.vue

@@ -1179,6 +1179,12 @@ export default {
                     if (this.joinFallbackTimer) { clearTimeout(this.joinFallbackTimer); this.joinFallbackTimer = null; }
                     const actualRoom = msg.to || msg.room || msg.roomName || '';
                     const desiredRoom = this.resolveInitialRoomName();
+                    if (actualRoom) {
+                        const matchingRoom = this.rooms.find((room) => (room.title || room.name) === actualRoom);
+                        if (matchingRoom) {
+                            this.selectedRoom = matchingRoom.id;
+                        }
+                    }
                     if (
                         this.adultOnlyMode
                         && desiredRoom
@@ -1194,13 +1200,15 @@ export default {
                         return;
                     }
                     // Eigene Beitrittsmeldung einmalig mit Raumname anzeigen
-                    if (!this.announcedRoomEnter) {
+                    if (!this.announcedRoomEnter || (this.adultOnlyMode && actualRoom && desiredRoom && actualRoom === desiredRoom)) {
                         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 });
                         }
-                        this.announcedRoomEnter = true;
+                        if (!this.adultOnlyMode || !desiredRoom || actualRoom === desiredRoom) {
+                            this.announcedRoomEnter = true;
+                        }
                     }
                     return;
                 }