This adds a Branch Deletion setting with three modes: disabled by
default, anyone with push access, or a restricted user/team/deploy-key
allowlist. The policy applies to Git pushes, API/UI deletion, and
post-merge cleanup; the default branch and the pull request target
branch remain undeletable.
Closes https://github.com/go-gitea/gitea/issues/33305
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Co-authored-by: Enoque Duarte <12515551+enoquefcd@users.noreply.github.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>