fix(test): harden migration container cleanup

- guard against a nil shared docker network after sync.Once initialization
- register best-effort cleanup for the v0.26.2 bootstrap container before assertions run

store/test/containers.go

@@ -67,12 +67,23 @@ func getTestNetwork(ctx context.Context) (*testcontainers.DockerNetwork, error)
 	return testDockerNetwork.Load(), networkErr
 }
 
+func requireTestNetwork(ctx context.Context) (*testcontainers.DockerNetwork, error) {
+	nw, err := getTestNetwork(ctx)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to create test network")
+	}
+	if nw == nil {
+		return nil, errors.New("test network is unavailable")
+	}
+	return nw, nil
+}
+
 // GetMySQLDSN starts a MySQL container (if not already running) and creates a fresh database for this test.
 func GetMySQLDSN(t *testing.T) string {
 	ctx := context.Background()
 
 	mysqlOnce.Do(func() {
-		nw, err := getTestNetwork(ctx)
+		nw, err := requireTestNetwork(ctx)
 		if err != nil {
 			t.Fatalf("failed to create test network: %v", err)
 		}
@@ -172,7 +183,7 @@ func GetPostgresDSN(t *testing.T) string {
 	ctx := context.Background()
 
 	postgresOnce.Do(func() {
-		nw, err := getTestNetwork(ctx)
+		nw, err := requireTestNetwork(ctx)
 		if err != nil {
 			t.Fatalf("failed to create test network: %v", err)
 		}
@@ -269,9 +280,9 @@ func StartMemosContainer(ctx context.Context, cfg MemosContainerConfig) (testcon
 		"MEMOS_MODE": "prod",
 	}
 
-	nw, err := getTestNetwork(ctx)
+	nw, err := requireTestNetwork(ctx)
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to create test network")
+		return nil, err
 	}
 
 	var opts []testcontainers.ContainerCustomizer

store/test/migrator_upgrade_test.go

@@ -31,6 +31,11 @@ func TestMigrationFromV0262PreservesLegacyData(t *testing.T) {
 	t.Logf("Starting Memos %s container for %s schema bootstrap...", cfg.Version, driver)
 	container, err := StartMemosContainer(ctx, cfg)
 	require.NoError(t, err, "failed to start v0.26.2 memos container")
+	t.Cleanup(func() {
+		if container != nil {
+			_ = container.Terminate(ctx)
+		}
+	})
 
 	legacyStore := NewTestingStoreWithDSN(ctx, t, driver, hostDSN)
 	require.Eventually(t, func() bool {
@@ -44,6 +49,7 @@ func TestMigrationFromV0262PreservesLegacyData(t *testing.T) {
 
 	err = container.Terminate(ctx)
 	require.NoError(t, err, "failed to stop v0.26.2 memos container")
+	container = nil
 
 	db := openMigrationSQLDB(t, driver, hostDSN)
 	defer db.Close()