Tempest v1.2 — velocity-sensitive spinner + USB mouse (working)

Tempest v1.2 — the spinner actually works now

v1.1 shipped USB spinner support that was implemented but never tested on a real
device, and it turned out to be broken in several independent ways. v1.2 fixes the
whole input path. Rotation is now confirmed on hardware with a USB mouse (which
is how most USB spinners enumerate).

Feel

• Velocity-sensitive: small movements nudge the tube one notch at a time; faster
  movements spin proportionally faster — and the direction is always correct, at
  any speed (it stays inside the game's 4-bit knob decode).
• Slow movement de-sensitized for fine aiming; fast flicks unchanged.

Controls

• USB mouse: move left/right to rotate, left button = Fire, right button =
  Superzapper.
• New OSD Spinner Reverse toggle if your device turns the wrong way.

Under the hood (for the curious)

• POKEY pot read corrected to MAME's model (the dial had been reading 0 forever).
• 2's-complement mouse-delta decode (fixed direction).
• Rate-paced ±1 stepper that never trips the 4-bit knob-inversion threshold.

Everything from v1.1 carries over: flicker-free vectors, 4K-clean integer scaling,
and the picture fills the screen.

Install

1. Copy Arcade-Tempest_20260602.rbf to /media/fat/_Arcade/cores/.
2. Copy Tempest.mra to /media/fat/_Arcade/.
3. Supply tempest.zip (MAME tempest) in /media/fat/games/mame/.
   ROMs are not included (Tempest is © 1981 Atari).