This update adds complete tenant management to the backend:
- Added tenant models, repositories, services, and handlers
- Added user registration flow that creates tenant + user in a transaction
- Added tenant retrieval endpoints (GetTenant, GetMyTenant)
- Configured new routes and integrated handlers into SetUpRoutes
- Wired repositories, services, and handlers into main.go
- Implemented slug generation, validation, and transactional creation logic
Includes updates across:
- models (tenants)
- repositories (tenant_repository)
- services (tenant_service)
- handlers (tenant_handler, user_handler)
- routes and main.go for full system integration
