Bluetooth Support for HID Devices

Currently, Bluetooth HID support in FreeBSD is limited to the bthidd daemon. The daemon, while functional, uses its own custom userspace drivers rather than the existing HID drivers in the kernel. Of these userspace drivers, only keyboards and mice are supported. This project proposes a more integrated design via a new Netgraph node type: ng_bthid. This node will hook to ng_l2cap and function as a virtual transport layer that interfaces directly with hidbus. The aim is to make HID support more transport-agnostic, moving away from the previous approach of maintaining separate, redundant drivers for devices over Bluetooth.