Token accounting operability report

Bounded local health metrics for the accounting system — ledger health, usage coverage by availability, mismatches, reconciliation backlog, unresolved age, write failures, submit-to-commit and commit latency digests, and the pinned counting service's handle/cache/queue counters, refusals and cold/warm latency digests. Counts, labels and durations only; no session, prompt or output content. Answers even when the ledger cannot be opened, because that state is the report.