spec-machine gap #4: production-as-teacher ingestion

[ahoward]

Vision: dna/product/vision-spec-machine.md (v4.0), principle 6 + the loop. Umbrella: #112. Lower priority; after gap #1.

Goal: extend the extraction pipeline to ingest runtime signals (prod traces, incidents, eval/test results) as evidence that promotes or contradicts claims — "production teaches the specification."

Acceptance:

• an adapter ingests at least one runtime signal type into episodes/claims with provenance.
• ingested evidence can support OR contradict an existing claim (ties to gap tests: /ping handler test cases #1 contradiction model).