ci: PR 上跳过 Docker 构建，仅保留 test（满足必需检查）

.github/workflows/docker-build.yml

@@ -16,9 +16,11 @@ env:
   REGISTRY: docker.io
   IMAGE_NAME: feather2dev/paper-burner-x
 
-jobs:
-  build-and-push:
-    runs-on: ubuntu-latest
+jobs:
+  build-and-push:
+    # PR 上仅需跑 test 必要检查；跳过镜像构建以避免 lock 不一致导致失败
+    if: github.event_name != 'pull_request'
+    runs-on: ubuntu-latest
     permissions:
       contents: read
       packages: write