Concurrency and Locking

Backlog field	Value
Story ID	CTRL-004
Epic	Cross Cutting Controls
Story type	Consistency control
Review status	Draft - business analyst and business owner review required
Source evidence	Draft-state checks, inventory-count locks, balance validation, remaining quantity checks, and unit-of-work boundaries
Last source review	2026-07-10

As an operational manager, I want concurrent users prevented from consuming the same stock, balance, credit, sequence, or returnable quantity so that results remain consistent.

Acceptance scenarios

Posting revalidates current state and balance inside the transaction. A second competing action receives a conflict/business error. An open inventory count locks warehouse movements. Needs confirmation: database concurrency tokens/retry policy for every aggregate.