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/repository/keto_outbox_repository.go

@@ -70,7 +70,7 @@ func (r *ketoOutboxRepository) ListCurrentBySubject(ctx context.Context, namespa
 }
 
 func (r *ketoOutboxRepository) UpdateStatus(ctx context.Context, id string, status string, retryCount int, lastError string) error {
-	return r.db.WithContext(ctx).Model(&domain.KetoOutbox{}).Where("id = ?", id).Updates(map[string]interface{}{
+	return r.db.WithContext(ctx).Model(&domain.KetoOutbox{}).Where("id = ?", id).Updates(map[string]any{
 		"status":      status,
 		"retry_count": retryCount,
 		"last_error":  lastError,
@@ -80,7 +80,7 @@ func (r *ketoOutboxRepository) UpdateStatus(ctx context.Context, id string, stat
 
 func (r *ketoOutboxRepository) MarkProcessed(ctx context.Context, id string) error {
 	now := time.Now()
-	return r.db.WithContext(ctx).Model(&domain.KetoOutbox{}).Where("id = ?", id).Updates(map[string]interface{}{
+	return r.db.WithContext(ctx).Model(&domain.KetoOutbox{}).Where("id = ?", id).Updates(map[string]any{
 		"status":       domain.KetoOutboxStatusProcessed,
 		"processed_at": &now,
 		"updated_at":   now,