fix(auth): accept email or identifier login payload

backend/internal/core/dto/user_auth.go

@@ -4,6 +4,7 @@ import "time"
 
 type LoginRequest struct {
 	Email      string `json:"email"`
+	Identifier string `json:"identifier"`
 	Password   string `json:"password"`
 }
 

backend/internal/core/usecases/auth/login.go

@@ -24,9 +24,18 @@ func NewLoginUseCase(userRepo ports.UserRepository, authService ports.AuthServic
 }
 
 func (uc *LoginUseCase) Execute(ctx context.Context, input dto.LoginRequest) (*dto.AuthResponse, error) {
+	loginID := strings.TrimSpace(input.Email)
+	if loginID == "" {
+		loginID = strings.TrimSpace(input.Identifier)
+	}
+
+	if loginID == "" {
+		return nil, errors.New("invalid credentials")
+	}
+
 	// 1. Find User by Email
-	fmt.Printf("[LOGIN DEBUG] Searching for user: %s\n", input.Email)
-	user, err := uc.userRepo.FindByEmail(ctx, input.Email)
+	fmt.Printf("[LOGIN DEBUG] Searching for user: %s\n", loginID)
+	user, err := uc.userRepo.FindByEmail(ctx, loginID)
 	if err != nil {
 		fmt.Printf("[LOGIN DEBUG] Error finding user: %v\n", err)
 		return nil, errors.New("invalid credentials")

backend/internal/core/usecases/auth/login_test.go

@@ -99,3 +99,42 @@ func TestLoginUseCase_Execute_StatusCheck(t *testing.T) {
 		})
 	}
 }
+
+func TestLoginUseCase_Execute_AcceptsIdentifierFallback(t *testing.T) {
+	authSvc := &MockAuthService{
+		GenerateTokenFunc: func(userID, tenantID string, roles []string) (string, error) {
+			return "mock-token", nil
+		},
+	}
+
+	calledWith := ""
+	userRepo := &MockUserRepo{
+		FindByEmailFunc: func(ctx context.Context, email string) (*entity.User, error) {
+			calledWith = email
+			return &entity.User{
+				ID:           "user-123",
+				Email:        "lol@gohorsejobs.com",
+				PasswordHash: "hashed_pass",
+				Status:       entity.UserStatusActive,
+				Roles:        []entity.Role{},
+			}, nil
+		},
+	}
+
+	uc := auth.NewLoginUseCase(userRepo, authSvc)
+
+	resp, err := uc.Execute(context.Background(), dto.LoginRequest{
+		Identifier: "lol@gohorsejobs.com",
+		Password:   "password",
+	})
+
+	if err != nil {
+		t.Fatalf("expected success with identifier, got error: %v", err)
+	}
+	if resp == nil {
+		t.Fatal("expected response, got nil")
+	}
+	if calledWith != "lol@gohorsejobs.com" {
+		t.Fatalf("expected repo lookup using identifier value, got %q", calledWith)
+	}
+}