Wire rule registry and authenticated callbacks into both client and server
runtimes; expose __yonexusClient / __yonexusServer on globalThis for
cross-plugin communication. Add Docker-based integration test with
server-test-plugin (test_ping echo) and client-test-plugin (test_pong
receiver), plus docker-compose setup. Fix transport race condition where
a stale _connections entry caused promoteToAuthenticated to silently fail.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
