- ARM_STEP_DEG 8 -> 3 and a dedicated ARM_MIN_GAP_MS of 60, so the arm
tracks the trigger instead of jumping between targets. Speed and spans
left as they were.
- hub1 port B is the tilt motor, C is the turn motor - swapped from what
the first build assumed.
- Zero the arm encoders once per boot rather than on every reconnect. The
hub keeps its preset, and re-zeroing mid-session would redefine zero at
whatever position the arms were in when the link dropped.