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/handler/auth_handler_qr_test.go

@@ -68,7 +68,7 @@ func TestQRLoginFlow_Success(t *testing.T) {
 	resp, _ := app.Test(req, -1)
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 
-	var initResp map[string]interface{}
+	var initResp map[string]any
 	json.NewDecoder(resp.Body).Decode(&initResp)
 	pendingRef := initResp["pendingRef"].(string)
 
@@ -80,7 +80,7 @@ func TestQRLoginFlow_Success(t *testing.T) {
 
 	// Expect authorization_pending (400)
 	assert.Equal(t, http.StatusBadRequest, resp.StatusCode)
-	var pollResp map[string]interface{}
+	var pollResp map[string]any
 	json.NewDecoder(resp.Body).Decode(&pollResp)
 	assert.Equal(t, "authorization_pending", pollResp["error"])
 	assert.Equal(t, "authorization_pending", pollResp["code"])
@@ -99,7 +99,7 @@ func TestQRLoginFlow_Success(t *testing.T) {
 
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 
-	var successResp map[string]interface{}
+	var successResp map[string]any
 	json.NewDecoder(resp.Body).Decode(&successResp)
 	assert.Equal(t, "ok", successResp["status"])
 	assert.Equal(t, "mock-session-jwt", successResp["sessionJwt"])
@@ -121,10 +121,10 @@ func TestScanQRLogin_Success(t *testing.T) {
 
 	transport := roundTripFunc(func(r *http.Request) (*http.Response, error) {
 		if r.URL.Path == "/sessions/whoami" {
-			return httpJSONAny(r, http.StatusOK, map[string]interface{}{
-				"identity": map[string]interface{}{
+			return httpJSONAny(r, http.StatusOK, map[string]any{
+				"identity": map[string]any{
 					"id": "user-123",
-					"traits": map[string]interface{}{
+					"traits": map[string]any{
 						"email": "user@example.com",
 					},
 				},
@@ -153,20 +153,20 @@ func TestResolveConsentSubjects_TokenAndCookie(t *testing.T) {
 
 	transport := roundTripFunc(func(r *http.Request) (*http.Response, error) {
 		if r.Header.Get("X-Session-Token") == "token-123" {
-			return httpJSONAny(r, http.StatusOK, map[string]interface{}{
-				"identity": map[string]interface{}{
+			return httpJSONAny(r, http.StatusOK, map[string]any{
+				"identity": map[string]any{
 					"id": "user-token",
-					"traits": map[string]interface{}{
+					"traits": map[string]any{
 						"email": "token@test.com",
 					},
 				},
 			}), nil
 		}
 		if r.Header.Get("Cookie") == "ory_kratos_session=cookie-123" {
-			return httpJSONAny(r, http.StatusOK, map[string]interface{}{
-				"identity": map[string]interface{}{
+			return httpJSONAny(r, http.StatusOK, map[string]any{
+				"identity": map[string]any{
 					"id": "user-cookie",
-					"traits": map[string]interface{}{
+					"traits": map[string]any{
 						"email": "cookie@test.com",
 						"phone": "010-1234-5678",
 					},