Complete design for TripDetailView refactor with constrained drag-and-drop:
- Games are fixed anchors (immovable, ordered by time)
- Travel is movable with hard constraints (after departure games, before arrival games)
- Custom items are freely movable anywhere
Key decisions from 100-question brainstorming session:
- Unified ItineraryItem model (replaces CustomItineraryItem + TravelDayOverride)
- Separate testable ItineraryConstraints type
- Full structure stored (not derived)
- Debounced sync, local-first, last-write-wins
- Invalid zones dim during drag, barrier games highlight
- Gap opens at drop position, haptic feedback throughout
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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