fix: ensure lib is built before examples:build (#185)

* fix: ensure lib is built before examples:build

Add preexamples:build hook to automatically run `npm run build` before
`examples:build`. This ensures examples always type-check against the
latest library code, catching breaking changes during development.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* feat: add version consistency check for examples

Add scripts/check-versions.mjs to verify that example package.json files
reference the correct version of @modelcontextprotocol/ext-apps.

- Allows "../.." (local dev) or "^{root-version}" as valid dependencies
- Runs in CI before npm install to catch mismatches early
- Available locally via `npm run check:versions`

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: regenerate package-lock.json for cross-platform compatibility

---------

Co-authored-by: Claude <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -36,6 +36,10 @@ jobs:
         shell: bash
         run: '! grep -E "\"resolved\": \"https?://" package-lock.json | grep -v registry.npmjs.org'
 
+      - name: Verify example dependency versions
+        shell: bash
+        run: node scripts/check-versions.mjs
+
       - uses: actions/setup-node@v4
         with:
           node-version: "20"