fix(devx): wire check:published-readme-exports' namespace branch and refuse the fourth no-population state (#10596)

Fixes #10367
Fixes #10417


Claude-Session: https://claude.ai/code/session_01DdCnBGcHeufjrq7drTD3wt

Co-authored-by: Claude <noreply@anthropic.com>

Author: claude[bot]