Improve local agent chat and device health detection

apps/device-host-agent/host_agent/heartbeat.py

@@ -60,6 +60,8 @@ class HeartbeatSynchronizer:
             self.status_tracker.mark_host_policy(self.policy)
 
     async def sync_once(self) -> HeartbeatResponse:
+        self.probe_connected_devices()
+        self.connect_devices()
         snapshot = build_device_snapshot(self.manager)
         mcp_busy_ids = (
             self.mcp_busy_tracker.busy_device_ids()
@@ -108,9 +110,19 @@ class HeartbeatSynchronizer:
 
     def connect_devices(self) -> None:
         for device in self.manager.list_devices():
-            if device.status != "idle":
+            if device.status not in {"idle", "offline", "error"}:
                 continue
             try:
                 self.manager.connect(device.id)
             except DeviceRuntimeError:
                 continue
+
+    def probe_connected_devices(self) -> None:
+        active_id: str | None = None
+        if self.status_tracker is not None:
+            current = self.status_tracker.snapshot().get("current_assignment")
+            if isinstance(current, dict) and isinstance(current.get("device_id"), str):
+                active_id = current["device_id"]
+        for device in self.manager.list_devices():
+            if device.id != active_id and device.status == "busy":
+                self.manager.probe(device.id)