fix: pass base_url and api_key directly to camel-ai ModelFactory

camel-ai does not read OPENAI_BASE_URL env var reliably.
Pass api_key and base_url via model_config_dict instead.

backend/scripts/run_parallel_simulation.py

@@ -1031,9 +1031,16 @@ def create_model(config: Dict[str, Any], use_boost: bool = False):
     
     print(f"{config_label} model={llm_model}, base_url={llm_base_url[:40] if llm_base_url else '默认'}...")
     
+    # Build model config dict for camel-ai
+    model_config = {"model_type": llm_model}
+    if llm_api_key:
+        model_config["api_key"] = llm_api_key
+    if llm_base_url:
+        model_config["base_url"] = llm_base_url
+    
     return ModelFactory.create(
         model_platform=ModelPlatformType.OPENAI,
-        model_type=llm_model,
+        model_config_dict=model_config,
     )