docs(changelog): drop pricing-refresh entry moved to #499

The models.dev snapshot refresh was split out of this PR into #499 because it
carries upstream semantic changes needing review. The changelog entry went with
it; this branch only changes unpriced-cost reporting.

Author: AWF Verification

CHANGELOG.md

@@ -5,7 +5,6 @@ Cross-package release notes for relayburn. Package changelogs contain package-le
 ## [Unreleased]
 
 - `burn summary` marks unpriced model rows and labels totals as priced-only; JSON adds `unpricedTurns` and `unpricedModels` so unknown-model spend is never mistaken for free usage.
-- Pricing: refreshed the vendored models.dev snapshot, including `gpt-5.6-sol`.
 
 ## [4.0.0] - 2026-06-23