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/schemas.py

@@ -46,7 +46,7 @@ class CreateRoomRequest(BaseModel):
     severity: SeverityLevel = Field(..., description="Severity level")
     location: Optional[str] = Field(None, max_length=255, description="Incident location")
     description: Optional[str] = Field(None, description="Detailed description")
-    template: Optional[str] = Field(None, description="Template name to use")
+    lots: Optional[List[str]] = Field(None, description="LOT batch numbers")
 
 
 class UpdateRoomRequest(BaseModel):
@@ -57,6 +57,7 @@ class UpdateRoomRequest(BaseModel):
     location: Optional[str] = Field(None, max_length=255)
     description: Optional[str] = None
     resolution_notes: Optional[str] = None
+    lots: Optional[List[str]] = Field(None, description="LOT batch numbers")
 
 
 class AddMemberRequest(BaseModel):
@@ -111,6 +112,7 @@ class RoomResponse(BaseModel):
     location: Optional[str] = None
     description: Optional[str] = None
     resolution_notes: Optional[str] = None
+    lots: List[str] = []
     created_by: str
     created_at: datetime
     resolved_at: Optional[datetime] = None
@@ -137,18 +139,9 @@ class RoomListResponse(BaseModel):
     offset: int
 
 
-class TemplateResponse(BaseModel):
-    """Room template information"""
-    template_id: int
-    name: str
-    description: Optional[str] = None
-    incident_type: IncidentType
-    default_severity: SeverityLevel
-    default_members: Optional[List[dict]] = None
-    metadata_fields: Optional[dict] = None
-
-    class Config:
-        from_attributes = True
+class AddLotRequest(BaseModel):
+    """Request to add a LOT to a room"""
+    lot: str = Field(..., min_length=1, description="LOT batch number to add")
 
 
 class PermissionResponse(BaseModel):