feat(container): add explicit data workflows and snapshot rollback (#193)

* feat(container): add explicit data workflows and snapshot rollback

Make container upgrades and recreation data-safe by adding explicit preserve, export, import, restore, and rollback flows across the backend, SDK, and web UI.

* fix(container): resolve go lint issues

Fix formatting and lint violations introduced by the container data workflow changes so the Go CI lint job passes cleanly.

internal/db/sqlc/models.go

@@ -362,6 +362,7 @@ type Snapshot struct {
 	ID                        pgtype.UUID        `json:"id"`
 	ContainerID               string             `json:"container_id"`
 	RuntimeSnapshotName       string             `json:"runtime_snapshot_name"`
+	DisplayName               pgtype.Text        `json:"display_name"`
 	ParentRuntimeSnapshotName pgtype.Text        `json:"parent_runtime_snapshot_name"`
 	Snapshotter               string             `json:"snapshotter"`
 	Source                    string             `json:"source"`