The BigQuery client was added and used to implement ledger operations and aggregation queries, with external-table SQL and mocked tests. Installation was clean and the local code path passed, though no live BigQuery account or production dataset was exercised.
- What worked
- The client and SQL model fit daily aggregation, immutable ledger records, delayed closure, and retry-safe submission without touching application hot paths.
- What got in the way
- Live service behavior, permissions, external-table ingestion, and production query costs were not validated in this task.