feat(integration): support Node.js extensions in local make test runs

[amylin1249]

Local make integration testing now supports Node.js extensions, so a Node/Express
extension can be developed and verified locally, not just in CI. This is
harness/tooling groundwork; it applies to whatever Node/Express example or
extension we ultimately build on top of it. Mirrors the same change already made in
connect-staging-extensions.

What changed

• nodejs-integration-test.sh (new): for appmode: nodejs extensions, starts
  Connect via with-connect, installs a Node runtime into the container (the
  published Connect images ship none), enables it, restarts, then runs the test.
  The Node build is architecture-matched (arm64/x64), so it works on Apple Silicon
  and on CI runners.
• Makefile: routes nodejs extensions to that script and leaves every other
  extension on the existing with-connect path; adds NODE_VERSION and 2026.06.0
  to the version list.
• package-extension: forces ustar format. macOS bsdtar defaults to pax, whose
  headers Connect's bundle reader cannot parse for a nested manifest ("Cannot open
  manifest"); ustar is read by both bsdtar and GNU tar.

Not in scope

• No Node extension content yet. The actual example/extension (Node + Express) is
  separate follow-up work and will build on this harness.
• CI-side Node support (provisioning, lint, engines.node) lands via Support Node.js content in the Gallery release pipeline #373/feat: support Node.js content in the gallery release pipeline #423;
  this is the local make counterpart.

Verified

Ran locally end-to-end against Connect 2026.06.0: a Node extension deploys and
returns HTTP 200, and a non-Node extension still deploys through the unchanged path.

[github-actions]

Extension release summary

😴 Changed but won't release

The following extensions have code changes but the manifest version hasn't been incremented:

• package-vulnerability-scanner: manifest version 3.0.6 ≤ released version 3.0.6
• publisher-command-center: manifest version 0.0.8 ≤ released version 0.0.8
• runtime-version-scanner: manifest version 1.0.5 ≤ released version 1.0.5
• usage-metrics-dashboard: manifest version 1.0.15 ≤ released version 1.0.15

If you intended to release these changes, update the version field in each extension's manifest.json.

See the contributing guide for details.