fix(ci): use raw git push for GitHub mirror

ad-m/github-push-action chokes on secret substitution in act_runner.
Use plain git commands instead — no third-party action needed.

.forgejo/workflows/mirror.yml

@@ -15,9 +15,6 @@ jobs:
           fetch-depth: 0
 
       - name: Push to GitHub mirror
-        uses: https://github.com/ad-m/github-push-action@master
-        with:
-          github_token: ${{ secrets.GH_MIRROR_TOKEN }}
-          repository: metamorphosis-dev/gosearch
-          branch: ${{ github.ref_name }}
-          force: true
+        run: |
+          git remote add github "https://x-access-token:${{ secrets.GH_MIRROR_TOKEN }}@github.com/metamorphosis-dev/kafka.git"
+          git push github "${{ github.ref_name }}" --force