Put terminal runs that were never metered back on the ledger

Writes a $0 run usage event for every TERMINAL run in this workspace that has none, so the metered-event count and the run count reconcile (E2E9-06). A run reaches this state when the API closes it because its Workflow is already gone — metering is one of the Workflow’s durable finalize steps, so it never ran. The amount is always ZERO: this is a reconciliation, never a late charge. Dry run unless apply=1. Idempotent: the ledger id is the one finalize would have used, so a finalize that arrives afterwards is a no-op rather than a double charge.