ci: build plugin before running tests

The dist-bundle regression tests in
src/shared/dist-bundle-bun-globals.test.ts are guarded by
`test.skipIf(!existsSync("dist/index.js"))` and dist/ is
gitignored, so they silently skipped in CI which ran tests before
the build step. Adding the build step earlier ensures the
regression guard runs and a future raw `Bun.*` leak in the bundle
fails CI.

.github/workflows/ci.yml

@@ -46,6 +46,9 @@ jobs:
         env:
           BUN_INSTALL_ALLOW_SCRIPTS: "@ast-grep/napi"
 
+      - name: Build plugin
+        run: bun run build
+
       - name: Run tests
         run: bun run script/run-ci-tests.ts