fix: pass base_url to Google and Anthropic clients for proxy support (#427)

tradingagents/llm_clients/google_client.py

@@ -27,6 +27,9 @@ class GoogleClient(BaseLLMClient):
         """Return configured ChatGoogleGenerativeAI instance."""
         llm_kwargs = {"model": self.model}
 
+        if self.base_url:
+            llm_kwargs["base_url"] = self.base_url
+
         for key in ("timeout", "max_retries", "callbacks", "http_client", "http_async_client"):
             if key in self.kwargs:
                 llm_kwargs[key] = self.kwargs[key]