Both Yonexus.Client and Yonexus.Server used module-level variables as
hot-reload guards, which reset on every hot-reload (new VM context).
Fix submodule pointers to the corrected plugin index.ts commits.
Also add LESSONS_LEARNED.md and OPENCLAW_PLUGIN_DEV.md (copied from
Dirigent) with three new lessons from this session (§11 connection-plugin
hot-reload trap, §12 transport message routing race, §13 re-hello on
session race) and updated plugin dev guide (§2.2 connection plugin entry
pattern, §6 state table, §9 checklist, §10 cross-plugin globalThis API).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>