refactor(controller): remove unused rightStickHorizontal binding

- Drop the Alt Horizontal row from Alt+C; no action read this binding
- Remove the key from config defaults, resolver, IPC validator, and types
- Regenerate config.example.jsonc and remove the inactive-binding exemption

src/config/definitions/defaults-core.ts

@@ -92,7 +92,6 @@ export const CORE_DEFAULT_CONFIG: Pick<
       playNextSubtitle: { kind: 'none' },
       leftStickHorizontal: { kind: 'axis', axisIndex: 0, dpadFallback: 'horizontal' },
       leftStickVertical: { kind: 'axis', axisIndex: 1, dpadFallback: 'vertical' },
-      rightStickHorizontal: { kind: 'axis', axisIndex: 3, dpadFallback: 'none' },
       rightStickVertical: { kind: 'axis', axisIndex: 4, dpadFallback: 'none' },
     },
     reviewBindings: getDefaultControllerReviewBindings(),