fix(devx): wire check:published-readme-exports' namespace branch and refuse the fourth no-population state

Fixes #10367
Fixes #10417

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DdCnBGcHeufjrq7drTD3wt

Author: claude