feat: add MCP server, A2A protocol, auto-combo engine & VS Code extension

Introduce full AI orchestration ecosystem:
- MCP Server with 16 tools, scoped auth, and audit logging
- A2A v0.3 server with JSON-RPC 2.0, SSE streaming, and task manager
- Auto-Combo engine with 6-factor scoring and self-healing
- VS Code extension with smart dispatch and budget tracking
- Harden CI pipeline: add static checks, remove continue-on-error
- Add translator schema validation tests
- Update .gitignore and CHANGELOG for release checklist

docs/RELEASE_CHECKLIST.md

@@ -0,0 +1,33 @@
+# Release Checklist
+
+Use this checklist before tagging or publishing a new OmniRoute release.
+
+## Version and Changelog
+
+1. Bump `package.json` version (`x.y.z`) in the release branch.
+2. Move release notes from `## [Unreleased]` in `CHANGELOG.md` to a dated section:
+   - `## [x.y.z] — YYYY-MM-DD`
+3. Keep `## [Unreleased]` as the first changelog section for upcoming work.
+4. Ensure the latest semver section in `CHANGELOG.md` equals `package.json` version.
+
+## API Docs
+
+1. Update `docs/openapi.yaml`:
+   - `info.version` must equal `package.json` version.
+2. Validate endpoint examples if API contracts changed.
+
+## Runtime Docs
+
+1. Review `docs/ARCHITECTURE.md` for storage/runtime drift.
+2. Review `docs/TROUBLESHOOTING.md` for env var and operational drift.
+3. Update localized docs if source docs changed significantly.
+
+## Automated Check
+
+Run the sync guard locally before opening PR:
+
+```bash
+npm run check:docs-sync
+```
+
+CI also runs this check in `.github/workflows/ci.yml` (lint job).