fix: restore VS Code extension validation baseline

[josedab]

Summary

• Repairs extension tests/config typing, pins the supported VS Code harness, and runs Electron tests headlessly in CI.
• Preserves repository public contracts while restoring or strengthening the verification baseline.
• Includes an AUDIT.md where the repository reached the audit/refactor phase.

Commits

• b46ce19 fix(vscode): restore extension validation baseline
• 4426e59 docs(vscode): record clean-code audit
• 86e86bf fix(ci): run extension tests headlessly

Validation

Compile, lint, 39 Electron tests, and VSIX packaging pass locally; branch CI is green.

Known blockers / deferred work

• None beyond required PR checks and documented AUDIT.md deferrals.

Merge readiness

Ready for review. Merge only after all required GitHub checks and reviewer approvals pass.