chore: add production build step to CI

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: B4nan

.github/workflows/ci.yml

@@ -26,3 +26,4 @@ jobs:
       - run: npm ci
       - run: npx tsc --noEmit
       - run: node ace test
+      - run: node ace build