Modernize CI/CD pipeline with comprehensive automation (#25)

* Initial plan

* Add comprehensive CI/CD workflows and tooling

- Add PR validation workflow with lint, format, type check, test, and build steps
- Improve Docker build workflow with caching, security scanning, and manual trigger
- Add CodeQL security analysis workflow
- Add Dependabot configuration for automated dependency updates
- Configure ESLint with TypeScript support
- Add npm scripts for linting and formatting
- Format code with Prettier
- Fix linting issues in source code

Co-authored-by: THoguet <61246905+THoguet@users.noreply.github.com>

* Update README and fix build configuration

- Add CI/CD documentation to README
- Document code quality tools and scripts
- Disable font optimization in production build to avoid network dependency
- Add build cache configuration for GitHub Actions

Co-authored-by: THoguet <61246905+THoguet@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: THoguet <61246905+THoguet@users.noreply.github.com>

.github/workflows/pr-validation.yml

@@ -0,0 +1,105 @@
+name: PR Validation
+
+on:
+    pull_request:
+        branches: [main]
+    push:
+        branches: [main]
+
+jobs:
+    lint:
+        name: Lint Check
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+
+            - name: Setup Node.js
+              uses: actions/setup-node@v4
+              with:
+                  node-version: '20'
+                  cache: 'npm'
+
+            - name: Install dependencies
+              run: npm ci
+
+            - name: Check code formatting with Prettier
+              run: npx prettier --check "src/**/*.{ts,html,scss,css,json}"
+
+            - name: Run ESLint
+              run: npx eslint "src/**/*.ts"
+
+    type-check:
+        name: TypeScript Type Check
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+
+            - name: Setup Node.js
+              uses: actions/setup-node@v4
+              with:
+                  node-version: '20'
+                  cache: 'npm'
+
+            - name: Install dependencies
+              run: npm ci
+
+            - name: Run TypeScript compiler
+              run: npx tsc --noEmit
+
+    test:
+        name: Unit Tests
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+
+            - name: Setup Node.js
+              uses: actions/setup-node@v4
+              with:
+                  node-version: '20'
+                  cache: 'npm'
+
+            - name: Install dependencies
+              run: npm ci
+
+            - name: Run unit tests
+              run: npm test -- --watch=false --browsers=ChromeHeadless --code-coverage
+
+            - name: Upload coverage reports
+              uses: codecov/codecov-action@v4
+              if: always()
+              with:
+                  token: ${{ secrets.CODECOV_TOKEN }}
+                  files: ./coverage/vac-optimizer/lcov.info
+                  fail_ci_if_error: false
+
+    build:
+        name: Build Application
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+
+            - name: Setup Node.js
+              uses: actions/setup-node@v4
+              with:
+                  node-version: '20'
+                  cache: 'npm'
+
+            - name: Install dependencies
+              run: npm ci
+
+            - name: Build production bundle
+              run: npm run build -- --configuration production
+              env:
+                  NG_BUILD_CACHE: '.angular/cache'
+
+            - name: Check bundle size
+              run: |
+                  du -sh dist/vac-optimizer/browser
+                  echo "Build completed successfully"
+
+            - name: Upload build artifacts
+              uses: actions/upload-artifact@v4
+              with:
+                  name: build-artifacts
+                  path: dist/
+                  retention-days: 7