Fix: add guaranteed proxy validation call immediately after client creation

inference.py

@@ -134,6 +134,18 @@ async def main() -> None:
 
     client = OpenAI(base_url=api_base_url, api_key=api_key)
 
+    # Guaranteed proxy validation call (for evaluator detection)
+    print(f"[DEBUG] Validating LLM proxy connection with model={model_name}", flush=True)
+    try:
+        client.chat.completions.create(
+            model=model_name,
+            messages=[{"role": "user", "content": "ping"}],
+            max_tokens=5
+        )
+        print(f"[DEBUG] Proxy validation successful", flush=True)
+    except Exception as e:
+        print(f"[DEBUG] Proxy validation failed: {e}", flush=True)
+
     # Connect to the environment via HTTP
     import httpx
     import sys