clean-all

Clean up all branches except main, locally and remotely.

1. Run git remote prune origin to remove stale remote tracking refs.
2. Delete all local branches except main: git branch | grep -v "main" | xargs git branch -D
3. Delete all remote branches except main: git branch -r | grep -v "origin/main\|origin/HEAD" | sed 's|origin/||' | xargs -I{} git push origin --delete {}
4. Remove any .claude/worktrees/* directories: git worktree remove each, then delete leftover empty dirs.
5. Verify with git branch -a and ls .claude/worktrees/ — only main should remain.
6. Report summary: how many local branches, remote branches, and worktrees were cleaned up.

If everything is already clean, just say so.