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/models/__init__.py

@@ -7,6 +7,7 @@ from .comment import TicketComment
 from .system import System
 from .category import Category
 from .client_profile import ClientProfile
+from .attachment import TicketAttachment
 
 __all__ = [
     "User",
@@ -15,5 +16,6 @@ __all__ = [
     "TicketComment",
     "System",
     "Category",
-    "ClientProfile"
+    "ClientProfile",
+    "TicketAttachment"
 ]