fix: Refactor D-Bus connection to use a single persistent instance

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

main.py

@@ -15,6 +15,8 @@ from dbus_next.service import ServiceInterface, method
 from dbus_next import Variant
 
 
+bus = None
+
 # --- Bluetooth constants and agent ---
 BLUEZ_SERVICE = 'org.bluez'
 ADAPTER_IFACE = 'org.bluez.Adapter1'
@@ -74,7 +76,6 @@ class Agent(ServiceInterface):
 async def trust_and_connect_device(device_path):
     logging.info(f'Trusting and connecting to {device_path}')
     try:
-        bus = await MessageBus().connect()
         introspection = await bus.introspect(BLUEZ_SERVICE, device_path)
         device_obj = bus.get_proxy_object(BLUEZ_SERVICE, device_path, introspection)
         
@@ -89,7 +90,6 @@ async def trust_and_connect_device(device_path):
         logging.error(f'Failed to trust/connect to {device_path}: {e}')
 
 async def get_adapter():
-    bus = await MessageBus().connect()
     introspection = await bus.introspect(BLUEZ_SERVICE, '/org/bluez')
     manager_obj = bus.get_proxy_object(BLUEZ_SERVICE, '/org/bluez', introspection)
     manager_iface = manager_obj.get_interface('org.freedesktop.DBus.ObjectManager')
@@ -102,7 +102,6 @@ async def get_adapter():
     return None
 
 async def register_agent():
-    bus = await MessageBus().connect()
     agent = Agent(AGENT_IFACE)
     bus.export(AGENT_PATH, agent)
 
@@ -182,11 +181,18 @@ async def fetch_mqtt():
             loop.create_task(process_mqtt(message))
 
 
-if __name__ == '__main__':
+async def main():
+    global bus
+    bus = await MessageBus().connect()
+
     logging.info('')
     logging.info('==========================')
     logging.info('Booting up...')
 
-    loop = asyncio.get_event_loop()
+    manage_task = asyncio.create_task(manage_bluetooth())
-    a = loop.create_task(manage_bluetooth())
+    mqtt_task = asyncio.create_task(fetch_mqtt())
-    loop.run_until_complete(fetch_mqtt())
+    await asyncio.gather(manage_task, mqtt_task)
+
+
+if __name__ == '__main__':
+    asyncio.run(main())