Audit fixes: a11y, gesture correctness, math edge cases

- Keyboard focus-visible ring on all controls (WCAG 2.4.7), suppressed
  for pointer grabs; focusRing prop to customize or disable
- aria-orientation on track modes; data-dragging/-disabled/-readonly/
  -focus-visible state attributes; disabled dims, readOnly drops the
  grab cursor
- Escape cancels a drag and restores the pre-gesture value
- Controlled mode no longer desyncs when the parent rejects onChange
- Second concurrent pointer can no longer hijack a drag session;
  drags cancel when disabled/readOnly flips mid-gesture
- Wheel: onChangeStart symmetry, settle flush on unsubscribe, dominant-
  axis direction (fixes macOS Shift+scroll reversal), ignored mid-drag
- Shift+wheel and fine multipliers now work on stepped/values knobs
- Fader/LEDFader track mapping inset-aligned with handle travel (no
  value jump when grabbing the cap); LEDFader zones sorted
- roundTo no longer returns NaN for exponential-notation values;
  logTaper falls back to linear for invalid ranges; decimalsFromStep
  shaves float noise; findClosest([]) returns the input
- Double-click reset brackets with onChangeStart/End
- MetalKnob honors showValue/unit/format; VintageKnob omits them from
  its type; TickLabels extracted as a public primitive
- SegmentDisplay: letters/hex charset, dash overflow instead of 888

apps/docs/src/sections/Playground.tsx

@@ -135,8 +135,10 @@ export const Playground: React.FC = () => {
         return <MetalKnob size={cfg.size} {...common} />;
       case 'rubber':
         return <RubberKnob size={cfg.size} {...common} />;
-      case 'vintage':
-        return <VintageKnob size={cfg.size} {...common} />;
+      case 'vintage': {
+        const { showValue: _sv, unit: _u, ...vintageProps } = common;
+        return <VintageKnob size={cfg.size} {...vintageProps} />;
+      }
       case 'led':
         return <LEDKnob size={cfg.size} {...common} />;
       case 'neon':