perf(cli): instant MCP startup — WS connects in background

Move startClients() to run after server.connect(), not before.
MCP server is available to Claude Code in <0.5s instead of ~30s.
Tool handlers gracefully return errors until WS is ready.
Push event wiring happens in background callback.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "claudemesh-cli",
-  "version": "0.9.0",
+  "version": "0.9.1",
   "description": "Claude Code MCP client for claudemesh — peer mesh messaging between Claude sessions.",
   "keywords": [
     "claude-code",