Assessment of auto-detecting worktrees created outside PI WEB. Worktree
discovery is already derived per request with no cache and no registry, so
the gap is that the browser never re-lists. Recommends the reduced scope:
filter prunable worktrees, add a non-disruptive topology refresh, and call
it from the existing browser-resume path. No watchers, timers, processes, or
push channels.
Packet is repo-only and outside the published files allowlist, so no
changeset is needed.
