feat(bluetooth): auto-connect paired & trusted devices with toggle control

Adds automatic reconnection of paired and trusted Bluetooth devices
when Bluetooth is enabled or when the shell starts. The feature is
fully toggleable ON/OFF from three places:

- Settings > Connections > Bluetooth (persistent NToggle)
- Bluetooth Panel quick toggle (NIconButton in header)
- IPC commands: toggleAutoConnect, enableAutoConnect, disableAutoConnect

Changes:
- New setting: bluetoothAutoConnect (default: true)
- Auto-trust devices upon pairing via Instantiator/Connections watcher
- 2s delay after BT enable to allow adapter initialization
- Respects airplane mode
- Toast notification when auto-connect fires

Services/Control/IPCService.qml

@@ -606,6 +606,15 @@ Singleton {
                                               bluetoothPanel?.toggle(null, "Bluetooth");
                                             });
     }
+    function toggleAutoConnect() {
+      Settings.data.network.bluetoothAutoConnect = !Settings.data.network.bluetoothAutoConnect;
+    }
+    function enableAutoConnect() {
+      Settings.data.network.bluetoothAutoConnect = true;
+    }
+    function disableAutoConnect() {
+      Settings.data.network.bluetoothAutoConnect = false;
+    }
   }
 
   IpcHandler {