refactor(admin): remove auth migration reports

backend/internal/handler/dto/mappers.go

@@ -21,7 +21,6 @@ func UserFromServiceShallow(u *service.User) *User {
 		Concurrency:                u.Concurrency,
 		Status:                     u.Status,
 		AllowedGroups:              u.AllowedGroups,
-		LastLoginAt:                u.LastLoginAt,
 		LastActiveAt:               u.LastActiveAt,
 		CreatedAt:                  u.CreatedAt,
 		UpdatedAt:                  u.UpdatedAt,

backend/internal/handler/dto/types.go

@@ -15,7 +15,6 @@ type User struct {
 	Concurrency   int        `json:"concurrency"`
 	Status        string     `json:"status"`
 	AllowedGroups []int64    `json:"allowed_groups"`
-	LastLoginAt   *time.Time `json:"last_login_at,omitempty"`
 	LastActiveAt  *time.Time `json:"last_active_at,omitempty"`
 	CreatedAt     time.Time  `json:"created_at"`
 	UpdatedAt     time.Time  `json:"updated_at"`

backend/internal/handler/dto/user_mapper_activity_test.go

@@ -21,16 +21,13 @@ func TestUserFromServiceAdmin_MapsActivityTimestamps(t *testing.T) {
 		Username:     "admin",
 		Role:         service.RoleAdmin,
 		Status:       service.StatusActive,
-		LastLoginAt:  &lastLoginAt,
 		LastActiveAt: &lastActiveAt,
 		LastUsedAt:   &lastUsedAt,
 	})
 
 	require.NotNil(t, out)
-	require.NotNil(t, out.LastLoginAt)
 	require.NotNil(t, out.LastActiveAt)
 	require.NotNil(t, out.LastUsedAt)
-	require.WithinDuration(t, lastLoginAt, *out.LastLoginAt, time.Second)
 	require.WithinDuration(t, lastActiveAt, *out.LastActiveAt, time.Second)
 	require.WithinDuration(t, lastUsedAt, *out.LastUsedAt, time.Second)
 }