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/service/developer_service.go

@@ -65,21 +65,21 @@ func (s *DeveloperService) ListRequests(ctx context.Context, userID, status stri
 }
 
 func (s *DeveloperService) ApproveRequest(ctx context.Context, id uint, adminNotes string) error {
-	return s.db.WithContext(ctx).Model(&domain.DeveloperRequest{}).Where("id = ?", id).Updates(map[string]interface{}{
+	return s.db.WithContext(ctx).Model(&domain.DeveloperRequest{}).Where("id = ?", id).Updates(map[string]any{
 		"status":      domain.DeveloperRequestStatusApproved,
 		"admin_notes": adminNotes,
 	}).Error
 }
 
 func (s *DeveloperService) RejectRequest(ctx context.Context, id uint, adminNotes string) error {
-	return s.db.WithContext(ctx).Model(&domain.DeveloperRequest{}).Where("id = ?", id).Updates(map[string]interface{}{
+	return s.db.WithContext(ctx).Model(&domain.DeveloperRequest{}).Where("id = ?", id).Updates(map[string]any{
 		"status":      domain.DeveloperRequestStatusRejected,
 		"admin_notes": adminNotes,
 	}).Error
 }
 
 func (s *DeveloperService) CancelApprovedRequest(ctx context.Context, id uint, adminNotes string) error {
-	return s.db.WithContext(ctx).Model(&domain.DeveloperRequest{}).Where("id = ?", id).Updates(map[string]interface{}{
+	return s.db.WithContext(ctx).Model(&domain.DeveloperRequest{}).Where("id = ?", id).Updates(map[string]any{
 		"status":      domain.DeveloperRequestStatusCancelled,
 		"admin_notes": adminNotes,
 	}).Error