feat: finalize Go backend migration and deployment cutover

.github/workflows/ci-build.yml

@@ -28,23 +28,25 @@ jobs:
         run: npm run build
 
   backend:
-    name: Build Backend
+    name: Build Go Backend
     runs-on: ubuntu-latest
     defaults:
       run:
-        working-directory: springboot-backend
+        working-directory: go-backend
     steps:
       - uses: actions/checkout@v4
 
-      - name: Setup Java 21
-        uses: actions/setup-java@v4
+      - name: Setup Go
+        uses: actions/setup-go@v5
         with:
-          java-version: '21'
-          distribution: 'temurin'
-          cache: 'maven'
+          go-version: '1.23'
+          cache-dependency-path: go-backend/go.sum
 
-      - name: Build with Maven
-        run: mvn clean package -DskipTests
+      - name: Download dependencies
+        run: go mod download
+
+      - name: Build
+        run: go build -v ./...
 
   agent:
     name: Build Agent