fix: add pre-restart delay to prevent MCP server failures on plugin updates

Add 2-second delay before worker restart in ensureWorkerVersionMatches() to
give files time to sync. Fixes issue where MCP server would fail after plugin
updates because restart happened too quickly.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugin/.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "claude-mem",
-  "version": "7.2.2",
+  "version": "7.2.3",
   "description": "Persistent memory system for Claude Code - seamlessly preserve context across sessions",
   "author": {
     "name": "Alex Newman"