Audit of post-fork param additions found CarCruiseDisplayActual was
written every CAN cycle (gated) but only consumed by hyundaicanfd.py::
create_buttons_alt, which has `return` on line 1 and no active callers.
Write was pure waste. Removed registration, write path, cache field,
and the dead read.
Also dropped the now-unused `from openpilot.common.params import Params`
in hyundaicanfd.py.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Brian Hanson
22ced0c558