Pending Ar Collections

Organizations whose automated dunning cadence has run out of automated steps and still carry a balance -- the AR/collections hat (Frederick, 2026-08-14, docs/01_decisions/ONE_ROOSTER_MANY_SKILLS.md).

Same {"conversations": [{"id": ...}, ...]} shape every other pending surface uses, so tools/rooster_worker/worker.py's existing fetch_pending drains it with no new client code. Read-only: deciding whether to escalate collections happens by filing a proposal through the supervision channel (POST /api/rooster/supervision/report), never by this route or any write this skill makes.