fix: single-line git clone for gitleaks container

Multiline run with backslash continuation gets corrupted inside
the gitleaks container. Collapse to single line.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -47,9 +47,7 @@ jobs:
       options: --entrypoint ""
     steps:
       - name: Checkout
-        run: |
+        run: git clone --branch "${GITHUB_REF_NAME}" "https://oauth2:${{ github.token }}@${GITHUB_SERVER_URL#https://}/${GITHUB_REPOSITORY}.git" .
-          git clone --branch "${GITHUB_REF_NAME}" \
-            "https://oauth2:${{ github.token }}@${GITHUB_SERVER_URL#https://}/${GITHUB_REPOSITORY}.git" .
       - name: Scan for secrets
         run: gitleaks detect --source . -v