Adds bring-up order (pair the pad before wiring, verify the port map with
DEBUG_MOTORS before trusting it), the tank drive control table, the extended
link protocol, and the wiring failure modes.
- Parse the extended frame (d-pad and analog triggers).
- Drive both hubs across all seven ports, one input per motor.
- Add a per-hub rate limit alongside the per-port one; hub1 has four
motors and the per-port throttle alone floods it.
- DEBUG_MOTORS flag to log which port each command lands on.
jessikitty