fix(test): rls fixture — reuse declared err variable

cmd/server/tests/rls_visibility_test.go

@@ -93,7 +93,7 @@ func TestRlsInvariant(t *testing.T) {
 
 	// Hide libH from the REGULAR user — the same row the admin
 	// visibility UI writes (harness idiom: SetLibraryVisibility).
-	_, err := setup.DB.SetLibraryVisibility(ctx, database.SetLibraryVisibilityParams{
+	_, err = setup.DB.SetLibraryVisibility(ctx, database.SetLibraryVisibilityParams{
 		UserID:    pgtype.UUID{Bytes: [16]byte(regularID), Valid: true},
 		LibraryID: libH.ID,
 		IsVisible: false,