Export bounded redacted governance-decision evidence

Downloads one filtered, fixed-sort-key-upper-bound view as CSV or JSON. Export is capped at 10,000 matching rows and returns 413 instead of truncating; narrow the filters and retry. request_context and delegation_chain are omitted from every row, CSV cells are protected against spreadsheet formula execution, and each successful export is recorded in the admin audit log. Rows remain authorization evidence, not invocation, payment, settlement, receipt, or task proof.