- Redesign card layout: priority label, description line, subtle shadow, configurable properties
- Wider columns (280px) with rounded background, count badge, and card spacing
- Add SortableContext for within-column drag reordering with fractional position indexing
- Fix collision detection to prefer card targets over column droppables for reliable down-drag
- Add hidden columns panel on right side with show/hide toggle
- Consolidate header into Filter popover (status + priority) and Display popover (ordering + card properties)
- Auto-switch to manual sort when cards are dragged to preserve drag ordering
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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