core

Selection step state management helpers

State Management Helpers

These helpers provide typed access to the selection step state in route handlers and duplicate audio source prevention.

Queue Response Builder

Shared response builder for handlers that mutate the selection queue. Three update patterns:

• Checkbox toggle (include_checkbox_oobs=False): queue + stats. The clicked checkbox already shows correct state. Items list is synced so future VC navigation renders correctly.
• Non-checkbox mutations (include_checkbox_oobs=True): queue + stats + OOB checkbox cells for visible rows. Used by Select All, Clear, Remove from queue panel.
• Queue-only (include_stats=False): queue only (e.g., reorder).