📝 Require concise prose in development/

Actionable sentence in CONTRIBUTING.md § Rules the tools don't enforce;
the why — humans skim, agents imitate the dominant style, so verbosity
compounds — in development/README.md § Decision blocks. Both sides in
one commit per the write-each-fact-once rule.

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - upgrade dependencies
 - ignore `@types/node` in `maintain:outdated` (misleading `latest` dist-tag)
+- require extremely concise prose in `development/`
 
 ## [0.1.7] - 2026-09-16