feat: Add Chat UX improvements with notifications and @mention support

- Add ActionBar component with expandable toolbar for mobile
- Add @mention functionality with autocomplete dropdown
- Add browser notification system (push, sound, vibration)
- Add NotificationSettings modal for user preferences
- Add mention badges on room list cards
- Add ReportPreview with Markdown rendering and copy/download
- Add message copy functionality with hover actions
- Add backend mentions field to messages with Alembic migration
- Add lots field to rooms, remove templates
- Optimize WebSocket database session handling
- Various UX polish (animations, accessibility)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/modules/chat_room/services/room_service.py

@@ -42,6 +42,7 @@ class RoomService:
             severity=room_data.severity,
             location=room_data.location,
             description=room_data.description,
+            lots=room_data.lots or [],
             status=RoomStatus.ACTIVE,
             created_by=user_id,
             created_at=datetime.utcnow(),
@@ -219,6 +220,9 @@ class RoomService:
         if updates.resolution_notes is not None:
             room.resolution_notes = updates.resolution_notes
 
+        if updates.lots is not None:
+            room.lots = updates.lots
+
         # Handle status transitions
         if updates.status is not None:
             if not self._validate_status_transition(room.status, updates.status):