ArduHumanoid: MAVLink - Controlled Humanoid Locomotion via ArduPilot SITL

ArduPilot flies over a million vehicles but has never controlled a humanoid, I intend to change this. I've spent the past several weeks building an 8-DOF humanoid in Gazebo Harmonic with ArduPilot SITL already connected, with the EKF3 reading attitude at 50Hz, joints responding, and the robot standing under real physics. During GSoC I'll extend it into a real platform with stable ZMP-based walking, active arms with reach and grasp, crouch and stand functions, MAVLink navigation commands, and a PR to ArduPilot main. By the end of summer ArduPilot will be able to command a humanoid to walk somewhere and interact with objects, using the same battle-tested infrastructure that already runs drones and rovers.