ci: docker-image.yml 补 pull_request 触发(此前仅 tag 构建, Dependabot PR 无测试门禁) + go vet 步骤

Author: tyza66

.github/workflows/docker-image.yml

@@ -1,7 +1,10 @@
 name: 'Docker 镜像构建'
 on:
   workflow_dispatch:
+  pull_request:
   push:
+    branches:
+      - main
     tags:
       - 'v*'
 permissions:
@@ -18,6 +21,8 @@ jobs:
         go-version: '1.25'
     - name: '杩愯娴嬭瘯'
       run: go test ./...
+    - name: '静态检查 go vet'
+      run: go vet ./...
     - name: '构建 Docker 镜像'
       run: |
         docker build -t simple-web-shell .