Reduced-rate modeld path now branches on IsDaylight:
- daylight: skip 1/2 frames → 10fps (better model responsiveness when
lighting gives the net more signal)
- night: skip 4/5 frames → 4fps (unchanged, conservative for power)
IsDaylight is already in /dev/shm (memory) via gpsd.py. Gated the
IsDaylight write on change — it flips twice a day, no reason to rewrite
every 30s. GPS polling bumped from 1Hz → 2Hz.
ModelFps publishes "10" / "4" / "20" so longitudinal_planner's dt and
FCW-threshold scaling (if re-enabled) still track actual rate.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>