Replace origin override with global option

- Remove origin parameter from connect() method
- Add ConnectOptions interface with global flag
- When global: true, sends X-Rondevu-Global header instead of trying to override Origin
- Update client methods to accept customHeaders parameter
- Pass custom headers through connection polling and ICE candidate exchange
- Bump version to 0.1.0

This change works around browser restriction on Origin header modification.

🤖 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": "0.0.6",
+  "version": "0.1.0",
   "description": "TypeScript client for Rondevu peer signaling and discovery server",
   "type": "module",
   "main": "dist/index.js",