fix(dispatch): liveness-aware coverage check, escalation rate limit, real alert sink

Prod findings (2026-09-22): a backend retry sweep failed 1,001 bookings in
60s; the agent called each a "coverage gap" because GEORADIUS found a miler
in the geo index (last seen in June), then sent 1,001 ops_alert tasks to
CUSTOMER_AGENT, which has no such handler.

- _find_zone filters GEORADIUS candidates by the backend's miler_status:<id>
  key; only status=Available counts. Facts now carry
  nearest_available_miler_within_km plus milers_in_geo_index_within_30km so
  the decision can separate "no riders here" from "riders exist, none on duty".
- Rate limit per zone per day: after the first alert, further failures only
  bump the counter (no LLM call); a summary re-alert goes out every
  DISPATCH_REALERT_EVERY (default 100).
- _ops_alert / _escalate_dispatch send EXCEPTION_DETECTED to JARVIS (the path
  that is actually handled); customer delay notice uses CUSTOMER_AGENT's real
  send_notification contract.
- JARVIS: escalation inbox (_escalations, pending_escalations()) and
  human_review/ops_alert task types are recorded instead of dropped.
- ExceptionAgent pull loops: also catch asyncio.TimeoutError (distinct from
  nats.errors.TimeoutError on 3.11) and log the exception type — the blank
  "pull loop error:" lines.
- Prompt + eval cases updated for the renamed facts; new case for the
  observed index-full/nobody-on-duty pattern. Tests for liveness filtering,
  burst suppression, fallback heuristic, sinks, and the JARVIS inbox.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012AJLYcbTHCe45fyFnMfEin

core/agent.py

@@ -208,6 +208,10 @@ class MasterAgent(Agent):
         self._sub_agents: Dict[str, Agent] = {}
         self._active_orders: Dict[str, Dict] = {}
         self._decision_log: List[Dict] = []
+        # Human-review inbox: every escalation/ops alert a sub-agent raised.
+        # The only sink for proposals the agents aren't authorised to act on;
+        # surfaced by pending_escalations() for the Command Center.
+        self._escalations: List[Dict] = []
 
     def register_sub_agent(self, agent: Agent):
         self._sub_agents[agent.agent_id] = agent
@@ -218,7 +222,7 @@ class MasterAgent(Agent):
         must decide) are logged at WARNING and recorded so they are visible
         rather than silently dropped — the endpoint of the human-review path."""
         if message.message_type == MessageType.EXCEPTION_DETECTED:
-            logger.warning(f"JARVIS: exception escalation from {message.sender}: {message.payload}")
+            self._record_escalation(message.sender, message.payload)
         else:
             logger.info(f"JARVIS: {message.message_type.value} from {message.sender}")
         self._decision_log.append({
@@ -240,9 +244,30 @@ class MasterAgent(Agent):
             return await self._handle_exception(task)
         elif task.task_type == "generate_report":
             return await self._generate_report(task)
+        elif task.task_type in ("human_review", "ops_alert"):
+            # Escalations sent as tasks land here instead of dead-lettering.
+            self._record_escalation(task.data.get("source", "unknown"), task.data)
+            return {"status": "recorded", "escalations_pending": len(self._escalations)}
         else:
+            logger.warning(f"JARVIS: unknown task type {task.task_type!r} — dropped")
             return {"status": "unknown_task", "task_type": task.task_type}
 
+    def _record_escalation(self, sender: str, payload: Dict[str, Any]):
+        logger.warning(f"JARVIS: escalation from {sender}: {payload}")
+        self._escalations.append({
+            "timestamp": datetime.now(),
+            "from": sender,
+            "exception_type": payload.get("exception_type"),
+            "severity": payload.get("severity"),
+            "payload": payload,
+        })
+        if len(self._escalations) > 500:
+            self._escalations = self._escalations[-500:]
+
+    def pending_escalations(self, limit: int = 50) -> List[Dict[str, Any]]:
+        """Most recent escalations first — the human-review inbox."""
+        return list(reversed(self._escalations[-limit:]))
+
     async def _orchestrate_order(self, task: AgentTask) -> Dict[str, Any]:
         order_data = task.data.get("order", {})
         order_id = order_data.get("order_id", "unknown")