Root causes addressed:
- track-list had no _itemSize hint for flow layout — virtualizer
defaulted to 100px, measured actual ~33px rows, then called
_correctScrollError/scrollTo on every scroll causing visible jumps
- will-change:transform on virtualizer elements caused nested GPU
layers (virtualizer positions children with transforms internally)
adding compositor overhead instead of helping
- content-visibility:auto on album cards conflicted with virtualizer's
own DOM recycling, causing redundant layout recalculation
- track-list visibilityChanged handler wrote to store synchronously
on every event (per-item during scroll) without any throttling
- IIFE closure in renderTrackRow created a new function per row per render
Fixes applied:
- Add _itemSize:{height:33} + fixed height:33px on .track-row (matches
queue-panel pattern that already worked smoothly)
- Add overflow-anchor:none on track-list virtualizer
- Remove will-change:transform from all 6 scroll containers
- Remove content-visibility:auto from album cards
- RAF-throttle visibilityChanged scroll position saves
- Replace IIFE with direct cols.map() in template