v1.108.139 — measured provenance rides the reporting surfaces

Added

• The measured-artifact block now attaches where the numbers get read. New measured_provenance() (retrieval/provenance.py) returns the committed measurement artifacts behind the suite's savings and quality claims — the tiktoken token-reduction methodology and the CI-gated replay retrieval golden, both drift-guarded against benchmarks/provenance/measured.json — and it now rides:
  • receipt --export json — a provenance block beside the totals, so an exported ledger carries its own receipts;
  • receipt text output — the methodology footer cites the committed artifact path;
  • get_session_stats — a savings_provenance block beside the savings figures;
  • jcodemunch_guide — a provenance key beside the policy snippet, so an agent reading the guide sees the declared-vs-measured contract up front.

Deliberately kept OFF the hot retrieval path: provenance rides the reporting surfaces a human or auditor reads, not every query.