Enforce config example drift checks in CI and release

- add `verify:config-example` script with tests to fail on missing/stale generated config artifacts
- run the verification in CI and release workflows, and document it in release/docs guidance
- fix docs-site Cloudflare Pages watch path to `docs-site/*` with regression coverage

docs/RELEASING.md

@@ -9,6 +9,7 @@
 4. Review `CHANGELOG.md`.
 5. Run release gate locally:
    `bun run changelog:check --version <version>`
+   `bun run verify:config-example`
    `bun run test:fast`
    `bun run typecheck`
 6. Commit release prep.