DOM bar chart with clip-overlay progress split; pointer-capture drag;
WaveformProfile fetched on load (fire-and-forget, cancellable); flat
fallback when no profile; small lazily-loaded waveformSeeker.js for
getBoundingClientRect and setPointerCapture.
Rename VolumeControls to VolumeZone; stack 24-bucket SpectrumVisualizer above volume
slider; remove it from PlayerSeekZone. MudSlider stays as seek placeholder. Pin
flex-shrink:0 on volume-zone; add Class param to VolumeZone for layout flexibility.
daniel-c-harvey