Refactor code structure for improved readability and maintainability

backend/app/services/llm/base_client.py

@@ -1,4 +1,3 @@
-# src/services/llm/base_client.py
 """LLM客户端基类 - 统一接口定义"""
 
 from abc import ABC, abstractmethod
@@ -113,4 +112,4 @@ class BaseLLMClient(ABC):
         # 中文字符约1.5 token，英文约0.25 token
         chinese_chars = sum(1 for c in text if '一' <= c <= '鿿')
         other_chars = len(text) - chinese_chars
-        return int(chinese_chars * 1.5 + other_chars * 0.25)
+        return int(chinese_chars * 1.5 + other_chars * 0.25)