The slider element had role="slider" and tabindex="0" but no keyboard
handler — the focus ring appeared but the slider could not be moved.
Add a keydown handler implementing the standard ARIA slider contract:
- ArrowLeft / ArrowDown — step left by 1 percent
- ArrowRight / ArrowUp — step right by 1 percent
- Shift + arrow — coarse step (10 percent)
- PageUp / PageDown — coarse step (10 percent)
- Home — jump to 0
- End — jump to 100
Bounds and step sizes extracted as named constants (SLIDER_MIN,
SLIDER_MAX, SLIDER_STEP_FINE, SLIDER_STEP_COARSE). Position updates go
through sliderSpring.target so keyboard moves animate the same way as
pointer drags.
Also adds the missing ARIA attributes that screen readers need:
- aria-valuemin / aria-valuemax (bounds)
- aria-orientation (horizontal)
Ilia Mashkov
410a7cd37e