Platform is no longer a self-balancing bot. Remove:
- TILT_CUTOFF_DEG (±25° tilt cutoff constant, was unused in ESP32-S3)
- BAL_TILT_FAULT state from bal_state_t enum (no code path generates it)
ESTOP and heartbeat watchdog are unchanged.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>