fix: update GitHub Actions test command for Vitest

Remove Karma-specific flags (--browsers, --no-watch, --no-progress)
that are not compatible with the Vitest test runner.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: gugu

.github/workflows/frontend.yml

@@ -13,7 +13,7 @@ jobs:
       - uses: actions/checkout@v2
       - run: cd frontend && yarn install
       - name: run tests
-        run: cd frontend && yarn test --browsers=ChromeHeadlessCustom --no-watch --no-progress
+        run: cd frontend && yarn test
   license:
     runs-on: ubuntu-latest
     steps: