- Add optional noChangeValue/noChangeLabel support to CustomModelDropdown so No change can coexist with Use default
- Update ListView bulk model controls to pass through a dedicated __no_change__ sentinel and avoid conflating untouched with clear-to-default
- Keep batch update payloads explicit by sending null provider/model only for Use default while leaving untouched lanes undefined
- Add dashboard tests covering No change vs explicit model vs Use default behavior and update README bulk-edit documentation