Make ordinary workspaces group shareable

internal/stage/extract.go

@@ -138,7 +138,7 @@ func (extractStage) Run(ctx context.Context, env *Env, m *manifest.Manifest) (*S
 		return nil, fmt.Errorf("extract: resolve durable bundle path: %w", err)
 	}
 	for _, directory := range []string{filepath.Dir(receiptPath), outputRoot, filepath.Dir(durableBundle)} {
-		if err := os.MkdirAll(directory, 0o755); err != nil {
+		if err := fileops.EnsureWorkspaceDirectory(directory); err != nil {
 			return nil, fmt.Errorf("extract: create directory %q: %w", directory, err)
 		}
 	}