- Add ui section to kindred-rd.yaml with category_picker (multi-stage),
item_fields, field_groups, category_field_groups, and field_overrides
- Add UIConfig structs to Go schema parser with full YAML/JSON tags
- Add ValidateUI() to validate field references against property schemas
- Add ValuesByDomain() helper to auto-derive subcategory picker stages
- Implement GET /api/schemas/{name}/form endpoint that returns resolved
form descriptor with field metadata, widget hints, and category picker
- Replace GET /api/schemas/{name}/properties route with /form
- Add FormDescriptor TypeScript types
- Create useFormDescriptor hook (replaces useCategories)
- Rewrite CreateItemPane to render all sections dynamically from descriptor
- Update CategoryPicker with multi-stage domain/subcategory selection
- Delete useCategories.ts (superseded by useFormDescriptor)
