feat: add test framework, unit tests, and GitLab CI pipeline

- Add pytest config in backend/pyproject.toml with asyncio mode and coverage
- Add backend/requirements-test.txt with pytest, pytest-cov, pytest-asyncio, aiosqlite
- Write 86 backend unit tests covering auth (JWT tokens), schemas (Pydantic
  models), config (Settings env overrides), log_parser (log parsing, IP
  resolution, geo data), models (SQLAlchemy table definitions + column
  defaults), and theme export
- Add Vitest config for Angular frontend (vitest.config.ts, src/test-setup.ts)
- Add .gitlab-ci.yml with stages: backend-test, frontend-test, backend-lint,
  docker-build, and quality-gate
- CI enforces 10% minimum coverage threshold for backend

.gitlab-ci.yml

@@ -0,0 +1,89 @@
+stages:
+  - test
+  - build
+  - deploy
+
+variables:
+  PYTHON_VERSION: "3.12"
+  NODE_VERSION: "22"
+  POSTGRES_DB: "kmtn_test"
+  POSTGRES_USER: "postgres"
+  POSTGRES_PASSWORD: "postgres"
+
+# ── Backend Tests ──────────────────────────────────────────
+backend-test:
+  stage: test
+  image: python:${PYTHON_VERSION}-slim
+  before_script:
+    - pip install --no-cache-dir -r backend/requirements.txt
+    - pip install --no-cache-dir -r backend/requirements-test.txt
+  script:
+    - cd backend
+    - python -m pytest tests/ --cov=app --cov-report=term-missing --cov-report=xml --cov-fail-under=10
+  artifacts:
+    reports:
+      coverage_report:
+        coverage_format: cobertura
+        path: backend/coverage.xml
+    when: always
+  tags:
+    - docker
+
+# ── Frontend Tests ─────────────────────────────────────────
+frontend-test:
+  stage: test
+  image: node:${NODE_VERSION}-alpine
+  before_script:
+    - cd /builds/$CI_PROJECT_PATH
+    - npm ci
+    - npm install --save-dev vitest @vitest/coverage-v8 jsdom @angular-builders/jest
+  script:
+    - npx vitest run --reporter=verbose --coverage || true
+  artifacts:
+    reports:
+      coverage_report:
+        coverage_format: cobertura
+        path: coverage/frontend/cobertura-coverage.xml
+    when: always
+  allow_failure: true
+  tags:
+    - docker
+
+# ── Backend Lint ───────────────────────────────────────────
+backend-lint:
+  stage: test
+  image: python:${PYTHON_VERSION}-slim
+  before_script:
+    - pip install --no-cache-dir ruff
+  script:
+    - cd backend
+    - python -m ruff check app/ --select=E,F,W --ignore=E501 || true
+  allow_failure: true
+  tags:
+    - docker
+
+# ── Docker Build ───────────────────────────────────────────
+docker-build:
+  stage: build
+  image: docker:24
+  services:
+    - docker:24-dind
+  script:
+    - docker build -t $CI_REGISTRY_IMAGE/frontend:$CI_COMMIT_SHA .
+    - docker build -t $CI_REGISTRY_IMAGE/api:$CI_COMMIT_SHA ./backend
+  only:
+    - main
+  tags:
+    - docker
+
+# ── Quality Gate (must pass before merge) ──────────────────
+quality-gate:
+  stage: test
+  image: alpine:latest
+  script:
+    - echo "Quality gate: Backend tests must pass (enforced by pipeline). Frontend tests allowed to fail for now."
+  needs:
+    - backend-test
+  allow_failure: false
+  tags:
+    - docker