Add Docker build and test job to CI workflow

Added a new job to build and test the Docker image for the carbon-server.

.github/workflows/ci.yml

@@ -84,3 +84,29 @@ jobs:
           name: code-quality-reports
           path: |
             cppcheck-report.txt
+
+  docker-build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Build Docker image
+        run: |
+          docker build -t carbon-server:test .
+      - name: Test Docker container startup
+        run: |
+          # Start container in background
+          docker run -d --name carbon-test -p 8080:8080 carbon-server:test
+          # Wait for server to start
+          sleep 5
+          # Check if container is running
+          docker ps | grep carbon-test
+          # Test HTTP endpoint
+          curl -f http://localhost:8080/ || exit 1
+          # Check logs for errors
+          docker logs carbon-test
+          # Stop container
+          docker stop carbon-test
+          docker rm carbon-test
+          echo "✓ Docker container started and responded successfully"