fix: replace actions/checkout@v4 with local git clone from Gitea

CI runner in China can't reach GitHub to download the checkout action.
Clone directly from internal Gitea container (http://gitea:3000) instead.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/test.yml

@@ -14,9 +14,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
+        run: |
+          if [ ! -d .git ]; then
+            git clone "http://gitea:3000/${GITHUB_REPOSITORY}.git" .
+          fi
         continue-on-error: true
 
       - name: Run gitleaks
@@ -38,9 +39,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
-        with:
-          fetch-depth: 1
+        run: |
+          if [ ! -d .git ]; then
+            git clone --depth=1 "http://gitea:3000/${GITHUB_REPOSITORY}.git" .
+          fi
 
       - name: Setup Python
         run: |
@@ -133,9 +135,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
-        with:
-          fetch-depth: 1
+        run: |
+          if [ ! -d .git ]; then
+            git clone --depth=1 "http://gitea:3000/${GITHUB_REPOSITORY}.git" .
+          fi
 
       - name: Setup Node.js
         run: |