standardize typed error responses across draft, pricing and publish endpoints
reduce contract drift between related flows
keep client-side handling more predictable and consistent
add backend read endpoints for single draft records
support direct fetch of individual draft entities
improve draft inspection and targeted editor workflows
- add typed response schemas for pricing write endpoints
- add stale draft version guard for pricing mutations
- unify pricing API contract around expected_scheme_version_id
- update API route map
- add smoke regression checklist for backend routes and artifact flows
add optimistic concurrency guards via expected scheme version id
protect draft editor, pricing snapshot, remap and publish flows from stale mutations
protect version creation from stale current version state
keep backward compatibility with optional query guards
verify 409 conflict behavior for stale clients and 200 for valid flows
