GitLab

- Fix gofmt formatting issue in user_service.go
- Remove unused sql field from userAttributeValueRepository
- Update ListWithFilters signature in test stubs to match interface
- Remove Wechat field from test user data

🤖 Generated with [Claude Code](https://claude.com/claude-code

)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Add a flexible user attribute system that allows admins to define
custom fields for users (text, textarea, number, email, url, date,
select, multi_select types).

- Add Ent schemas for UserAttributeDefinition and UserAttributeValue
- Add service layer with validation logic
- Add repository layer with batch operations support
- Add admin API endpoints for CRUD and reorder operations
- Add batch API for loading attribute values for multiple users
- Add database migration (018_user_attributes.sql)

🤖 Generated with [Claude Code](https://claude.com/claude-code

)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>