ci: improve image tag handling and add staging to security scan

.gitea/workflows/build-image.yml

@@ -828,7 +828,11 @@ jobs:
           DEPLOYMENT_HOST="${{ env.DEPLOYMENT_HOST }}"
           REGISTRY="${{ env.REGISTRY }}"
           IMAGE_NAME="${{ env.IMAGE_NAME }}"
-          IMAGE_TAG="latest"
+          IMAGE_TAG="${{ needs.build.outputs.image_tag || 'latest' }}"
+          
+          if [ -z "$IMAGE_TAG" ] || [ "$IMAGE_TAG" = "null" ]; then
+            IMAGE_TAG="latest"
+          fi
           
           FULL_IMAGE="${REGISTRY}/${IMAGE_NAME}:${IMAGE_TAG}"
           STACK_PATH="~/deployment/stacks/staging"