add gemini

app/llm.py

@@ -209,7 +209,7 @@ class LLMClient:
         url = self.base_url
         headers = {"Content-Type": "application/json"}
         if self.api_key:
-            headers["X-Goog-Api-Key"] = f"Bearer {self.api_key}"
+            headers["X-Goog-Api-Key"] = f"{self.api_key}"
         # Gemini API expects {"contents": [{"parts": [{"text": prompt}]}]}
         payload = {"contents": [{"parts": [{"text": prompt}]}]}
         response = await call_endpoint_with_retry(self._client, url, payload, headers=headers)