Add declarative VS Code skill extension packaging (#775)

* Add declarative VS Code skill extension packaging

Stage a launcher-only Copilot skill bundle, validate relocation and VSIX packaging, and keep project-install hooks out of the extension.

AI assistance: Codex, under maintainer direction.

* Document verified Copilot extension smoke test

Record the successful read-only VS Code 1.136.1 run and the reload required after initial workspace trust. Keep minimum-version and remote smoke gaps explicit.

AI assistance: Codex, under maintainer direction.

* Fix VS Code packaging test version source

Derive the provider fixture version from the skill manifest and assert the packaged skill and extension versions agree.

AI assistance: Codex, under maintainer direction.

scripts/test-suites.mjs

@@ -33,6 +33,7 @@ export const SUITES = {
       /^skill\/(SKILL\.src\.md|agents\/|reference\/|scripts\/)/,
       /^ENGINE_VERSION$/,
       /^README(\.npm)?\.md$/,
+      /^vscode\//,
       /^\.github\/workflows\/release-engine\.yml$/,
       /^cli\/bin\//,
     ],
@@ -72,6 +73,7 @@ export const SUITES = {
           'tests/github-sheriff.test.mjs',
           'tests/hook-build.test.mjs',
           'tests/openai-plugin.test.mjs',
+          'tests/vscode-extension.test.mjs',
           'tests/process-group.test.mjs',
           'tests/release.test.mjs',
           'tests/bundle-signing.test.mjs',