feat(swarm-worker): dispatch prose swarm slots to ephemeral Muse subagents

- daemon: route non-shell slot tasks to a fresh subagent session on dev/def/muse
  via muse_hybrid; add bin/ to sys.path so muse_hybrid/prompt_envelope import
  under the tmux supervisor
- prompt_envelope: add wrap_subagent_task() - plain task assignment without
  [TOOL tmux/swarm/cron] meta tags (subagents refused those as relayed test traffic)
- box-ctl/reporter: swarm-attach accepts optional session-id, stored as
  slot.subagent_session_id
- executor: _looks_like_shell requires an existing executable (prose like
  'verify ...' no longer misread as shell)
- poller: pick up pending swarms as well as running
- response-harvester: monitor running slot subagent sessions from swarms.json,
  allow '/' in RESULT/VERB job ids, archive ephemeral threads on any verdict
  (OK or FAIL), reap slot sessions for terminal swarms

bin/swarm_worker/poller.py

@@ -97,7 +97,8 @@ def find_pending_slots(stale_minutes=STALE_MINUTES):
         return found
     swarms = data.get("swarms", []) if isinstance(data, dict) else []
     for summary in swarms:
-        if (summary.get("status") or "").lower() != "running":
+        summary_status = (summary.get("status") or "").lower()
+        if summary_status not in ("running", "pending"):
             continue
         swarm_id = summary.get("swarm_id")
         if not swarm_id: