[loop-cycle-1] fix: use config for xAI base URL (#647) (#655)

src/timmy/backends.py

@@ -99,23 +99,27 @@ class GrokBackend:
 
     def _get_client(self):
         """Create OpenAI client configured for xAI endpoint."""
+        from config import settings
+
         import httpx
         from openai import OpenAI
 
         return OpenAI(
             api_key=self._api_key,
-            base_url="https://api.x.ai/v1",
+            base_url=settings.xai_base_url,
             timeout=httpx.Timeout(300.0),
         )
 
     async def _get_async_client(self):
         """Create async OpenAI client configured for xAI endpoint."""
+        from config import settings
+
         import httpx
         from openai import AsyncOpenAI
 
         return AsyncOpenAI(
             api_key=self._api_key,
-            base_url="https://api.x.ai/v1",
+            base_url=settings.xai_base_url,
             timeout=httpx.Timeout(300.0),
         )