Cross-Window Drag & Drop Refinement & Topology

[tobiu]

This epic tracks the advanced refinement and functional expansion of the Cross-Window Drag & Drop system ("Infinite Canvas").

Scope:

1. Theming Strategy:

   • Implement configurable behavior for dragged items: themeMode: 'adapt' | 'retain'.
   • Ensure items dropped into a different app/window correctly adopt (or resist) the target's theme.

2. Topology & Validation (Sender/Receiver Rules):

   • Enhance SortZone validation to support asymmetric flows (e.g., Inner Dashboard -> Main Dashboard allowed, but Main -> Inner blocked).
   • Implement allowDrop(draggedItem, sourceZone) hooks.

3. "Return Trip" Robustness (A -> B -> A):

   • Verify and harden the logic for dragging an item out of Window A, hovering Window B, and returning to Window A.
   • Ensure state tracking (detachedItems) remains consistent and the original dashboard correctly reclaims its item without duplication or state loss.

4. Architecture & Documentation:

   • Review DragCoordinator responsibility (is it doing too much visual calculation?).
   • Comprehensive JSDoc cleanup across SortZone, DashboardSortZone, and DragCoordinator.