fix(ci): add build step to test shards, fix cli-alias lint

- Add `pnpm build` step to test-shards job so plugin dist/ and core
  packages are compiled before tests run (fixes plugin-loader test)
- Add cli-alias/index.js to ESLint node scripts pattern so Node globals
  (process, AbortController, fetch) are recognized

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/pr-checks.yml

@@ -88,5 +88,8 @@ jobs:
       - name: Install Bun
         uses: oven-sh/setup-bun@v2
 
+      - name: Build
+        run: pnpm build
+
       - name: Test (deterministic shard)
         run: pnpm test:ci:shard --shard ${{ matrix.shard }} --total 3