Census existing disclosed_fields / audit disclosed rows for leaked jq operand text (follow-up to #538)

[angel-manuel]

Follow-up to #538, which stopped services/disclosure.rs from putting raw jaq error text on DisclosedField.error. That fix is forward-only: rows written before it may still carry a redacted value inside an error string.

The fix PR could not run this check — the agent's environment has no Cloud SQL reachability (gcloud sql instances list returns nothing for its service account). Someone with dev + prod DB access needs to run:

-- approvals still holding a disclosed error string
SELECT count(*) FROM approvals
WHERE jsonb_path_exists(disclosed_fields, '$[*].error');

-- audit rows likewise
SELECT count(*) FROM audit_log
WHERE jsonb_path_exists(detail, '$.disclosed[*].error');

A non-zero count is not automatically a leak — filter produced more than N values and a plain cannot index null with "x" carry nothing sensitive. The ones that matter start with cannot index , cannot calculate or cannot use and name a path the same template listed under x-overslash-redact. Sample the matched rows before deciding.

If there are real hits, the backfill is a targeted jsonb rewrite replacing each error with the fixed classification the code now emits. audit_log is otherwise append-only, so rewriting it is a decision worth making explicitly rather than as a side effect.