Two follow-ups to PR #1221's merge-fields behavior, both raised by the
Copilot review on that PR:
- Evidence merge now prefixes each entry with `Tier-1 heuristic: ` or
`Tier-2 LLM: ` so the on-disk `origin.json` audit record retains tier
provenance. The pre-#1221 code labeled heuristic evidence; the
merge-fields refactor flattened that. Re-prefixing is idempotent.
- Tests now assert that the merged `confidence` is the heuristic's, not
the LLM's. Added inline assertions to the two existing
contradiction/disagreement tests, plus a dedicated
`test_merge_tier_fields_confidence_matches_heuristic_call` that
compares to `detect_origin_heuristic` directly so a future regression
letting Tier 2 confidence leak through cannot pass silently.
Tests: 1378 pass. Ruff check + format both clean (CI-pinned 0.4.x).
Igor Lins e Silva
c92256f08f