Detect broken git hooks by checking if the commit id of branches in DB
is the same with the git repo.
It can help #29338#28277 and maybe more issues.
Users could complain about actions, webhooks, and activities not
working, but they were not aware that it is caused by broken git hooks
unless they could see a warning.
<img width="1348" alt="image"
src="https://github.com/go-gitea/gitea/assets/9418365/2b92a46d-7f1d-4115-bef4-9f970bd695da">
It should be merged after #29493. Otherwise, users could see a ephemeral
warning after committing and opening the repo home page immediately.
And it also waits for #29495, since the doc link (the anchor part) will
be updated.
---------
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>
(cherry picked from commit a4bcfb8ef1d5b2b522f78c9560d53ddbdbb02218)
963df82907