Spike: drag & drop reordering design #149

Goal

Investigate and design the drag & drop reordering feature for task lists. This spike produces a design document with decisions and mockups, not working code.

Research questions

• How does reorder interact with sort options? When a sort is active, should reordering be disabled since the sort defines the order?
• How is reorder state persisted? A sortOrder field on the task? Something else?
• Can users drag tasks between day groups on the Upcoming screen, or only reorder within a group?
• What touch/pointer interaction patterns work across platforms (Android, iOS, Desktop)?
• What are the accessibility considerations?
• Edge cases: scrolling during drag, long lists, cross-platform differences.

Dependencies

• Upcoming screen: day-grouped task list #138 (Upcoming screen: day-grouped task list)
• Sort by date (due date, creation date) #140 (Sort by date)

Deliverables

• Design document with decisions for each research question
• Mockups showing drag & drop visual feedback and interaction states
• Recommendation that feeds into Configure Android App to Use Version Catalog for SDK and Version Values #24 (Drag & drop reordering implementation)