fix(ci): start Jekyll server before performance tests

The performance tests were failing because they tried to connect to
localhost:4000 but the server was never started. Added server startup
and wait-on steps before running Lighthouse tests.

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

Co-Authored-By: Claude <[email protected]>

Author: aledlie

.github/workflows/test.yml

@@ -46,7 +46,13 @@ jobs:
       run: npm run test:e2e
       env:
         CI: true
-        
+
+    - name: Start Jekyll server for performance tests
+      run: bundle exec jekyll serve --detach
+
+    - name: Wait for Jekyll server
+      run: npx wait-on http://localhost:4000 --timeout 60000
+
     - name: Run performance tests
       run: npm run test:performance
       env: