fix(ci): drop force push from GitLab mirror workflow

GitLab.com protected branch rejects force push. Regular push is
safer anyway — fails loudly if mirror diverges.

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

Author: matthew-on-git

.github/workflows/mirror.yml

@@ -21,4 +21,4 @@ jobs:
           echo "$GITLAB_MIRROR_SSH_KEY" | ssh-add -
           mkdir -p ~/.ssh
           ssh-keyscan gitlab.com >> ~/.ssh/known_hosts
-          git push --force git@gitlab.com:devrail-dev/gitlab-repo-template.git HEAD:main
+          git push git@gitlab.com:devrail-dev/gitlab-repo-template.git HEAD:main