docs(changelog): one summary line for 1.0.3, not two

`release.mjs` inserts its own npm-only "_npm 1.0.3 (full lockstep…)_" line when it
promotes [Unreleased], which landed directly above the four-registry summary written for
this coordinated cut — the same claim twice, the first of them narrower than what shipped.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011cQxyVuTkdPmAduLiedNEg

Author: dmealing

CHANGELOG.md

@@ -12,9 +12,7 @@ here.**
 
 ## [1.0.3] — 2026-09-12
 
-_npm `1.0.3` (full lockstep across all 14 `@metaobjectsdev/*` publish candidates)._
-
-_All four registries publish: npm `1.0.3` (full lockstep across the 14 `@metaobjectsdev/*`
+_All four registries publish: npm `1.0.3` (full lockstep across all 14 `@metaobjectsdev/*`
 publish candidates), Maven Central `8.0.3`, PyPI `1.0.3`, NuGet `1.0.3`. PyPI and NuGet were
 last cut at `1.0.1` and adopt the shared `minor.patch` now current, skipping the number they
 sat out (ADR-0035 Amendment 1)._