tasks

Redesign Stack Builder with Toggleable Multi-Column Layout and Cross-Column Drag-Drop

Today's StackBuilder is a single-column 'Current stack' editor — aspirational and abandoned entries are only reachable by scrolling far below and editing the markdown frontmatter by hand. Redesign as a wider three-bucket canvas with pill toggles for which buckets are visible, two-up side-by-side view when two are active, and drag-and-drop to move tools across buckets. Cross-column moves reshape data (notes ↔ intent ↔ reason) with inline prompts so nothing is silently lost. Mobile gracefully degrades to a tap-to-move modal.