Scope credit accounts and retry receipts to the tenant

Independent tenants collide when they reuse an account ID or request key. Trace account lookup and unit-of-work receipt identity. Both identities must include tenant with unambiguous tuple encoding. An exact same-tenant retry returns its original snapshot without another audit row; a changed payload with the same key remains a request-conflict.

Work with the stack you want to practice. Your workspace and timer start after you choose.