Consider adding pruning of refs to git maintenance

Remote-tracking refs accumulate quickly in large repositories as users merge and delete their branches. While these branches are cleaned up on the remote, local repositories may retain stale references to deleted branches unless explicitly pruned. The number of local refs can have an impact on git performance of several commands.

Git currently provides two ways for orphan local refs to be cleaned up —
1. Automated: `fetch.prune` and `fetch.pruneTags` configurations with
`git fetch/pull`
2. Manual: `git remote prune`

However, both approaches have issues:
- Full `git fetch/pull` operations are expensive on large
repositories, pulling thousands of irrelevant refs
- Manual `git remote prune` requires user intervention

Proposal: Add remote pruning to the daily `git-maintenance` task. This would clean stale refs automatically without requiring full fetches or manual intervention.

This is especially useful for users who historically pulled all refs/tags but now use targeted fetches. Moreover, it decouples the cleanup action (pruning) from the action to fetch more refs.

Happy to submit on a patch for the same unless there's something obvious that I've missed here.