expenses — events

The module emits and consumes no events.

Expense rows are static accounting facts (amount + date + category); nothing else in the tree needs to react to their lifecycle asynchronously, and there is no denormalized state to keep in sync — so there is nothing to transact under ADR 0019. If a future module needs to react (e.g. accounting_export picking expenses into a ledger), add an EventType.EXPENSE_* constant plus a transactional publisher at that point.