fix: remove maven install, use Docker multi-stage build

.gitea/workflows/build.yml

@@ -15,7 +15,7 @@ jobs:
     steps:
       - name: Install build tools
         run: |
-          apk add --no-cache curl git docker-cli maven 2>/dev/null || true
+          apk add --no-cache curl git docker-cli 2>/dev/null || true
 
       - name: Clone + prepare
         run: |
@@ -30,11 +30,6 @@ jobs:
         env:
           HARBOR_PASSWORD: ${{ secrets.HARBOR_PASSWORD }}
 
-      - name: Build with Maven
-        run: |
-          cd /root/.cache/${{ env.APP_NAME }}
-          mvn clean package -DskipTests
-
       - name: Build & push Docker image
         run: |
           cd /root/.cache/${{ env.APP_NAME }}