The plan assumed no code existed yet, but the 2.5D-map autonomy stack
(URDF, terrain-aware speed control, Nav2 global/local costmaps +
collision monitor) is already built and running in the separate
fori_ws workspace. Reframes the doc around what's actually there and
the concrete gaps found (AMCL correction not wired into the nav TF
tree, skid-steer calibration not ported from xbox_motor_control.cpp).