重构模型管理和配置加载逻辑，支持多模态和推理模型，优化API密钥管理，改进前端模型选择和版本显示

models/base.py

@@ -2,9 +2,10 @@ from abc import ABC, abstractmethod
 from typing import Generator, Any
 
 class BaseModel(ABC):
-    def __init__(self, api_key: str, temperature: float = 0.7, system_prompt: str = None):
+    def __init__(self, api_key: str, temperature: float = 0.7, system_prompt: str = None, language: str = None):
         self.api_key = api_key
         self.temperature = temperature
+        self.language = language
         self.system_prompt = system_prompt or self.get_default_system_prompt()
 
     @abstractmethod