fix: 修复阿里云容器镜像仓库认证失败问题

- 增加 Docker 登录验证步骤
- 添加构建重试机制
- 优化认证流程稳定性
- 增强错误处理和日志输出

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.gitea/workflows/deploy-backend.yml

@@ -54,6 +54,16 @@ jobs:
           registry: ${{ env.REGISTRY }}
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_PASSWORD }}
+        env:
+          DOCKER_CLI_EXPERIMENTAL: enabled
+
+      - name: 🔍 验证镜像仓库连接
+        run: |
+          echo "🔍 验证镜像仓库连接..."
+          docker pull hello-world:latest || true
+          docker logout ${{ env.REGISTRY }} || true
+          echo "🏷️  重新登录镜像仓库..."
+          echo "${{ secrets.DOCKER_PASSWORD }}" | docker login ${{ env.REGISTRY }} --username "${{ secrets.DOCKER_USERNAME }}" --password-stdin
 
       - name: 📝 提取元数据
         id: meta
@@ -79,6 +89,23 @@ jobs:
           cache-to: type=gha,mode=max
           provenance: false
           sbom: false
+        continue-on-error: true
+        id: build_push
+
+      - name: 🔄 重试构建和推送
+        if: steps.build_push.outcome == 'failure'
+        run: |
+          echo "⚠️  构建推送失败，等待10秒后重试..."
+          sleep 10
+          docker buildx build --push \
+            --platform linux/amd64 \
+            --tag ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ github.sha }} \
+            --tag ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest \
+            --cache-from type=gha \
+            --cache-to type=gha,mode=max \
+            --provenance=false \
+            --sbom=false \
+            ./backend
 
       - name: 📦 同步配置文件
         run: |