ci: enforce 80% backend coverage gate and add frontend coverage reporting

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

.github/workflows/ci.yml

@@ -48,7 +48,7 @@ jobs:
         run: pip install -r backend/requirements.txt -r backend/requirements-dev.txt
 
       - name: Run tests with coverage
-        run: cd backend && python -m pytest --override-ini="addopts=" --cov=app --cov-report=term-missing --cov-report=json:coverage.json
+        run: cd backend && python -m pytest --override-ini="addopts=" --cov=app --cov-report=term-missing --cov-report=json:coverage.json --cov-fail-under=80
 
       - name: Display coverage summary
         if: always()
@@ -89,8 +89,8 @@ jobs:
       - name: Lint
         run: cd frontend && npm run lint
 
-      - name: Test
-        run: cd frontend && npm test
+      - name: Test with coverage
+        run: cd frontend && npm run test:coverage
 
       - name: Build
         run: cd frontend && npm run build