When a room was unregistered first (room_settings row already gone), the
folder was unknown, so sessions rows and the on-disk group/workspace/session/
ipc folders (and any git worktree) were silently skipped — leaving orphans.
Back-trace the folder from the group_folder recorded on the chat's leftover
paired_tasks/work_items/scheduled_tasks/service_handoffs/paired_projects rows
so folder-scoped cleanup still runs. Targets now carry a folder list.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>