Update chat to use google-genai SDK instead of REST API

app.py

@@ -112,39 +112,18 @@ async def chat_with_gemini(request: ChatRequest):
     Test Gemini API connectivity.
     Uses GEMINI_API_KEY from environment.
     """
-    import requests
-    
-    api_key = config.gemini_api_key or os.getenv("GEMINI_API_KEY")
-    if not api_key:
-        return {"error": "GEMINI_API_KEY not configured"}
-    
     try:
-        # Use Gemini REST API directly
-        url = f"https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash:generateContent?key={api_key}"
-        
-        payload = {
-            "contents": [{
-                "parts": [{"text": request.message}]
-            }]
-        }
-        
-        response = requests.post(url, json=payload, timeout=30)
-        
-        if response.status_code != 200:
-            return {"error": f"Gemini API error: {response.status_code} - {response.text[:200]}"}
+        from google import genai
         
-        data = response.json()
+        # Client gets API key from GEMINI_API_KEY environment variable
+        client = genai.Client()
         
-        # Extract reply
-        candidates = data.get("candidates", [])
-        if candidates:
-            content = candidates[0].get("content", {})
-            parts = content.get("parts", [])
-            if parts:
-                reply = parts[0].get("text", "No response")
-                return {"reply": reply}
+        response = client.models.generate_content(
+            model="gemini-2.5-flash",
+            contents=request.message
+        )
         
-        return {"error": "No response from Gemini"}
+        return {"reply": response.text}
         
     except Exception as e:
         logger.error(f"Gemini chat error: {e}")