feat(user): support fixed UUID registration and enhance bulk import results

- Added support for fixed UUIDs during bulk registration (Search-first + ExternalID mapping)
- Implemented idempotency and visibility restoration for soft-deleted users
- Enhanced bulk upload UI to show 'New/Updated/Unchanged' status and modified fields
- Added logic to reclaim identifiers (login_id) from colliding records
- Added frontend E2E and backend unit tests for UUID integrity and conflict handling
- Fixed i18n, formatting, and mock tests to satisfy code-check
- Applied 'go fix' for 'omitzero' tags and general Go standards

backend/internal/bootstrap/sync_admin.go

@@ -54,7 +54,7 @@ func SyncAdminRole(db *gorm.DB, kratosID string) error {
 	}
 
 	// Update role if needed
-	updates := map[string]interface{}{}
+	updates := map[string]any{}
 	if user.Role != domain.RoleSuperAdmin {
 		updates["role"] = domain.RoleSuperAdmin
 	}