Observe whether an exported bank source was subsequently reversed or changed

Verified bank-bound customer PERSON identity with customer scope, session/device and online account organization membership required. Writes require authentication within five minutes; API keys, staff and service impersonation refused. Existing maker/approver/admin roles and amount limits apply. Expense review requires distinct users AND person customer IDs. Pending/approved allocations reserve exact bank-source and receipt totals; duplicate bytes cannot be relabeled. Actual unreversed committed card journals are revalidated. Pre-export coding corrections preserve source/receipt/amount. Immutable customer-expense-json-1 exports contain balanced customer-book entries, exact review/source proofs and unique expense membership. Preparation/download never claims provider delivery/import, and never posts customer expense codes to bank GLs. See services/cards/spend/README.md. Observes current source state separately from the immutable historical artifact; a later bank journal reversal flags affected expense IDs without rewriting a previous export.