Adds 42 Vitest unit tests for the two composables extracted from the
admin categories page in ERP-50.
- useCategoriesAdmin (14 tests): fetchAll/fetchTypes, includeDeleted toggle,
loading flags, error handling, reset, singleton sharing.
- useCategoryForm (28 tests): validation rules RG-1.02/1.04/1.05, trim,
POST/PATCH/DELETE wiring, 409 (RG-1.07) and 422 violation mapping,
isDirty, loadFrom, reset, instance isolation.
Mocks useApi/useI18n/useToast via vi.stubGlobal and ~/shared/stores/auth
to keep the suite hermetic (no backend required).
tristan
091ccb6f28