fix: enumerate Pinscape devices once per process, not per Cabinet

[jsm174]

After researching vpinball/vpinball#3309, device enumeration was running inside the Cabinet constructor, so every game start re-walked the HID bus and re-opened the Pinscape while SDL was actively reading its joystick interface. The bus walk briefly stalled the joystick endpoint, which VPX's nudge filter interpreted as a large acceleration spike.

• Pinscape/PinscapePico Initialize() now skips FindDevices() if devices are already populated
• ClearDevices() moved out of OutputControllerList::Finish() (per-game) into IOConfigurator::Shutdown()
• Matches the C# reference, where enumeration lives in a static constructor and runs once per process