Development record

The shell guard refuses git worktree remove for a worktree whose HEAD is on origin/main and whose status is clean, whenever the worktree holds ignored files: a local tier with notes in it, an empty .abcd/.work.local, or the issue allocator's lock file. It also refuses a detached HEAD that sits on origin/main. In the 31 Oct cleanup it refused all 85 merged, clean worktrees, about 7.2 GB, even though every local tier had first been archived to the machine backup store. Reclaiming them takes one guard allow per worktree from the person.