fix(ci): replace checkout action with native git commands

Bypass Node.js requirement in host execution mode by using system git.

.gitea/workflows/test-ci.yml

@@ -17,10 +17,11 @@ jobs:
     name: Secret Detection (Gitleaks)
     runs-on: host
     steps:
-      - name: Check Out Code
-        uses: actions/checkout@v3
-        with:
-          fetch-depth: 0
+      - name: Fetch Code
+        run: |
+          git config --global --add safe.directory "$PWD"
+          git fetch --all
+          git checkout $GITEA_SHA
 
       - name: Run Gitleaks Scan
         run: |