feat(loop): codify external intrinsic loop management, progressive remediation, and operational runbook

- Add bin/gravity.py loop diagnostics, reconstruction, and progressive remediation
- Wire hard-break alerting to job-log audit and operator direct message
- Add comprehensive architecture and operational specification in docs/LOOP-MANAGEMENT.md
- Add sidechat thread auto-provisioning fallback on 'Navigated to: None' in bin/dm.py
- Support Muse unconfirmed signup error handling in bin/muse-signin.py
- Track dynamic pipe sidechat mappings in job-sidechats.json

bin/dm.py

@@ -320,7 +320,7 @@ def dm_send(agent, target, message, verify=True, raw=False,
     # cmd_sidechat_use exits 0 even on NOTFOUND (it prints "Navigated to: NOTFOUND").
     # If sidechat is not found, auto-provision a new thread via `sidechat create`!
     if target != "main":
-        if "NOTFOUND" in _out:
+        if "NOTFOUND" in _out or "Navigated to: None" in _out:
             log_event({"type": "sidechat_autoprovision_start", "id": msg_id, "agent": agent,
                        "to": recipient, "target": target})
             _c_rc, _c_out, _c_err = run_full(f"{NETVM_EXEC} {recipient} -- python3 {API} --account {recipient} sidechat create")