fix: never park the last present family as absent

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Uc9V1v7iXruubpoLiSE24M

hbd/client/main.py

@@ -626,7 +626,6 @@ async def async_main(args, config):
     loop.add_signal_handler(signal.SIGHUP, _sighup)
     
     # Start async tasks
-    # Heartbeat senders (one per connection)
     # Per-protocol internet presence probe (shared with the network_monitor plugin)
     net_cfg = dict((config.get("plugins") or {}).get("network_monitor")
                    or config.get("network_monitor") or {})
@@ -636,6 +635,7 @@ async def async_main(args, config):
         set_shared(connectivity)
         active_tasks.append(asyncio.create_task(connectivity.run(shutdown_event)))
 
+    # Heartbeat senders (one per connection)
     for conn in connections:
         task = asyncio.create_task(heartbeat_sender(conn, interval, connectivity))
         active_tasks.append(task)