Enhance test jobs with caching, coverage, and parallel execution

CI improvements:
- Add needs: [] to run tests parallel with build (faster pipeline)
- Add pip/npm caching (faster subsequent runs)
- Add 15m timeout to prevent hung jobs
- Add pytest coverage with cobertura report for GitLab
- Add pytest JUnit report for test tab in MR
- Add vitest coverage with cobertura report for GitLab
- Add coverage regex for badge display

Frontend:
- Add @vitest/coverage-v8 dependency
- Configure vitest coverage reporter (text, cobertura, html)

.gitlab-ci.yml

@@ -18,23 +18,62 @@ hadolint:
 # Run Python backend tests
 python_tests:
   stage: test
+  needs: []  # Run in parallel with build
   image: deps.global.bsf.tools/docker/python:3.12-slim
+  timeout: 15m
+  variables:
+    PIP_CACHE_DIR: "$CI_PROJECT_DIR/.pip-cache"
+  cache:
+    key: pip-$CI_COMMIT_REF_SLUG
+    paths:
+      - .pip-cache/
+    policy: pull-push
   before_script:
     - pip install -r backend/requirements.txt
-    - pip install pytest pytest-asyncio httpx
+    - pip install pytest pytest-asyncio pytest-cov httpx
   script:
     - cd backend
-    - python -m pytest -v
+    - python -m pytest -v --cov=app --cov-report=term --cov-report=xml:coverage.xml --cov-report=html:coverage_html --junitxml=pytest-report.xml
+  artifacts:
+    when: always
+    expire_in: 1 week
+    paths:
+      - backend/coverage.xml
+      - backend/coverage_html/
+      - backend/pytest-report.xml
+    reports:
+      junit: backend/pytest-report.xml
+      coverage_report:
+        coverage_format: cobertura
+        path: backend/coverage.xml
+  coverage: '/TOTAL.*\s+(\d+%)/'
 
 # Run frontend tests
 frontend_tests:
   stage: test
+  needs: []  # Run in parallel with build
   image: deps.global.bsf.tools/docker/node:20-alpine
+  timeout: 15m
+  cache:
+    key: npm-$CI_COMMIT_REF_SLUG
+    paths:
+      - frontend/node_modules/
+    policy: pull-push
   before_script:
     - cd frontend
     - npm ci
   script:
-    - npm run test -- --run
+    - npm run test -- --run --reporter=verbose --coverage
+  artifacts:
+    when: always
+    expire_in: 1 week
+    paths:
+      - frontend/coverage/
+    reports:
+      coverage_report:
+        coverage_format: cobertura
+        path: frontend/coverage/cobertura-coverage.xml
+  coverage: '/All files[^|]*\|[^|]*\s+([\d\.]+)/'
   rules:
     - exists:
         - frontend/package.json