Six public API functions had no callers anywhere in the firmware:
splash_prev, splash_set_active, splash_current_name, splash_count,
ble_is_connected, imu_set_rotation, power_is_usb_connected,
power_usb_changed. Trimming them lets power.cpp drop the VBUS state
machine (cached_usb, usb_changed_flag, last_vbus_ms,
enableVbusVoltageMeasure). usage_rate_reset becomes file-static since
the only caller is in usage_rate.cpp itself. Montserrat font flags in
platformio.ini were enabled but never referenced.
Hermann Björgvin Haraldsson
f1feacb3dc