ci: add Docker smoke test for health and version endpoints

Author: ibetitsmike

.github/workflows/ci.yml

@@ -171,6 +171,72 @@ jobs:
         env:
           ELECTRON_DISABLE_SANDBOX: 1
 
+  docker-smoke-test:
+    name: Docker Smoke Test
+    runs-on: ${{ github.repository_owner == 'coder' && 'depot-ubuntu-22.04-16' || 'ubuntu-latest' }}
+    if: github.event.inputs.test_filter == ''
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0 # Required for git describe to find tags
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build Docker image
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          load: true
+          tags: mux-server:test
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+      - name: Start container
+        run: |
+          docker run -d --name mux-test -p 3000:3000 mux-server:test
+          # Wait for server to be ready
+          for i in {1..30}; do
+            if curl -sf http://localhost:3000/health; then
+              echo "Server is ready"
+              break
+            fi
+            echo "Waiting for server... ($i/30)"
+            sleep 1
+          done
+
+      - name: Health check
+        run: |
+          response=$(curl -sf http://localhost:3000/health)
+          echo "Health response: $response"
+          if ! echo "$response" | grep -q '"status":"ok"'; then
+            echo "Health check failed"
+            exit 1
+          fi
+
+      - name: Version check
+        run: |
+          response=$(curl -sf http://localhost:3000/version)
+          echo "Version response: $response"
+          # Verify response contains expected fields
+          if ! echo "$response" | grep -q '"mode":"server"'; then
+            echo "Version check failed: missing mode=server"
+            exit 1
+          fi
+          if ! echo "$response" | grep -q '"version"'; then
+            echo "Version check failed: missing version field"
+            exit 1
+          fi
+
+      - name: Show container logs on failure
+        if: failure()
+        run: docker logs mux-test
+
+      - name: Cleanup
+        if: always()
+        run: docker rm -f mux-test || true
+
   check-codex-comments:
     name: Check Codex Comments
     runs-on: ${{ github.repository_owner == 'coder' && 'depot-ubuntu-22.04-16' || 'ubuntu-latest' }}