feat(backend): Update models and endpoints configuration

- Enhanced ticket and comment models with proper relationships
- Updated client_profile model for better data handling
- Improved auth endpoint with better error handling
- Updated main app configuration and imports
- Added new dependencies to requirements.txt
- Enhanced tickets endpoint with attachment support

backend/app/main.py

@@ -22,6 +22,7 @@ from app.models.category import Category
 from app.models.user import User
 from app.models.ticket import Ticket
 from app.models.comment import TicketComment
+from app.models.attachment import TicketAttachment
 
 from app.core.logging import setup_logging
 from app.api.v1.router import api_router