- Add new PrefillGroup model with CRUD operations
* Support for model, tag, and endpoint group types
* JSON storage for group items with GORM datatypes
* Automatic database migration support
- Implement backend API endpoints
* GET /api/prefill_group - List groups by type with admin auth
* POST /api/prefill_group - Create new groups
* PUT /api/prefill_group - Update existing groups
* DELETE /api/prefill_group/:id - Delete groups
- Add comprehensive frontend management interface
* PrefillGroupManagement component for group listing
* EditPrefillGroupModal for group creation/editing
* Integration with EditModelModal for auto-filling
* Responsive design with CardTable and SideSheet
- Enhance model editing workflow
* Tag group selection with auto-fill functionality
* Endpoint group selection with auto-fill functionality
* Seamless integration with existing model forms
- Create reusable UI components
* Extract common rendering utilities to models/ui/
* Shared renderLimitedItems and renderDescription functions
* Consistent styling across all model-related components
- Improve user experience
* Empty state illustrations matching existing patterns
* Fixed column positioning for operation buttons
* Item content display with +x indicators for overflow
* Tooltip support for long descriptions
