Switch initiator to @onpointerdown; capture the pointer on the knob element through a new knob.ts helper so pointermove/up/cancel reach the knob even when the cursor leaves the window. Accurate comment; IAsyncDisposable cleanup.
Greyer panel ground (token); remove drag scrollbar + lock body scroll; caption icons light; center WAVE slider; RadialKnob drag uses pointer events (robust to cursor leaving window); milder scrim alpha; overlay z-index above header/footer.