chore: bump version to 2.2.0

v2.2.0 — first fully working plugin release:
- Fix: resolve workspace dir from hook context (_ctx), not api.runtime
- Fix: strip channel metadata from user messages before state extraction
- Both fixes are required for gateway/Telegram/Discord deployments

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

openclaw.plugin.json

@@ -2,7 +2,7 @@
   "id": "memory-continuity",
   "name": "Memory Continuity",
   "description": "Preserves working state across /new, reset, compaction, and gateway restarts via a simple markdown checkpoint file.",
-  "version": "2.1.0",
+  "version": "2.2.0",
   "source": "https://github.com/dtzp555-max/memory-continuity",
   "configSchema": {
     "type": "object",