ci: use mirrored checkout action

Switch workflow checkout step to internal Gitea mirrored actions-checkout to reduce external GitHub dependency and speed up setup.

Made-with: Cursor

.github/workflows/release_skill.yaml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       # 1. 下载源码
-      - uses: actions/checkout@v3
+      - uses: http://120.25.191.12:3000/admin/actions-checkout@v4
 
       # 2. 环境及工具准备
       - name: Setup Tools