v1.108.138 — confidence provenance: every number states its basis

Added

• Confidence provenance registry (retrieval/provenance.py). Every confidence constant the suite emits traces to a stated basis: measured — backed by a committed, reproducible benchmark artifact (benchmarks/provenance/measured.json: the tiktoken token-reduction methodology and the CI-gated replay retrieval-quality golden) — or declared — an engineering prior, honestly labeled as exactly that. The contract's load-bearing rule: a prior is never presented as a measurement. A declared value graduates to measured only when a gold-labeled corpus backs it, and tests/test_provenance.py fails the build otherwise. Drift guards run in three directions: registry values must equal the live constants in the emitting modules, registry measured entries must equal the committed artifact, and the artifact must equal the underlying benchmark results it cites.
• find_implementations responses carry _meta.confidence_provenance — the per-channel basis for its resolution-confidence tiers (LSP / SCIP / AST / duck-typed / decorator), so a caller can see that today's tiers are declared priors, not measurements dressed up as ones.
• Published response JSON Schemas in schemas/: retrieval-verdict.schema.json (the unified _meta.verdict contract), confidence-provenance.schema.json, and ranked-context-response.schema.json (the full get_ranked_context JSON surface). CI validates live responses against them; external pipelines and agents can do the same.