Add default baseUrl and origin override support

- Set default baseUrl to 'https://rondevu.xtrdev.workers.dev' in RondevuOptions
- Make baseUrl optional in Rondevu constructor
- Add optional origin parameter to connect() method for per-connection origin override
- Bump version to 0.0.5

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

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@xtr-dev/rondevu-client",
-  "version": "0.0.4",
+  "version": "0.0.5",
   "description": "TypeScript client for Rondevu peer signaling and discovery server",
   "type": "module",
   "main": "dist/index.js",