feat(proxy): add xai upstream adapter for Grok via OAuth

hermes_cli/proxy/adapters/__init__.py

@@ -9,11 +9,13 @@ from typing import Dict, Type
 
 from hermes_cli.proxy.adapters.base import UpstreamAdapter
 from hermes_cli.proxy.adapters.nous_portal import NousPortalAdapter
+from hermes_cli.proxy.adapters.xai import XAIGrokAdapter
 
 # Registry of available adapter classes keyed by provider name as used on
 # the ``hermes proxy start --provider <name>`` CLI flag.
 ADAPTERS: Dict[str, Type[UpstreamAdapter]] = {
     "nous": NousPortalAdapter,
+    "xai": XAIGrokAdapter,
 }