perf(skills): optimize sleeps and modularize duplication with multi-agent consensus PASS

- OP-1: Implement reactive _wait_session_gone in lib.sh and stop_session.sh with set -e || true guard
- OP-2: Event-driven MQTT subscribe handshake with sub_pid liveness in delegate-job
- OP-3: Replace CPU time.sleep(0.5) spin with threading.Event wait in reconcile.sh
- OP-4: Define mam_tmux dispatcher targeting resolved _REAL_TMUX_PATH to prevent recursion
- OP-6 & OP-7: Add token variables and bash version source check in lib.sh
- Integrate approved optimization plan and PASS review reports from all agents

.agents/skills/multi-agent-mux-delegate-job/scripts/job_subscriber.py

@@ -185,8 +185,13 @@ def main(argv=None) -> int:
         if rc != 0:
             logger.warning("broker disconnected (rc=%s); will retry reconnect", reason_code)
 
+    def on_subscribe(_c, _u, mid, granted_qos, _props=None):
+        for topic in subscribed_topics:
+            print(f"SUBSCRIBED {topic}", flush=True)
+
     client.on_connect = on_connect
     client.on_disconnect = on_disconnect
+    client.on_subscribe = on_subscribe
     client.reconnect_delay_set(min_delay=1, max_delay=16)
     mqtt_common.with_retry(
         lambda: client.connect(config.host, config.port, config.keepalive),