- 14_TREE_API_DESIGN.md: complete design document with flat inventory + query manager architecture
- 15_FLAT_INVENTORY_QUERY_MANAGER.md: scheme comparison and key decisions
- TASK_TREE_API_IMPLEMENTATION.md: implementation task list for antigravity
- HANDOFF_TREE_API.md: task handoff brief
Key design decisions:
- template_key deduplication (venue+room+section, not per-session)
- group_by parameter for frontend to specify hierarchy order
- flat_inventory returned in full for client-side spec_key prefix matching
- zero additional API calls during seat selection flow
Council