feat(translator): 添加llama-cpp-python库可用性检查

在翻译功能中添加对llama-cpp-python库的可用性检查，当库未安装时显示警告信息并禁用翻译功能

translator.py

@@ -1,16 +1,29 @@
-from llama_cpp import Llama
 import os
 from utils.logger import logger
 
+# 尝试导入llama_cpp，如果失败则设置Llama为None
+try:
+    from llama_cpp import Llama
+    llama_cpp_available = True
+except ImportError:
+    logger.warning("llama-cpp-python库未找到，将禁用翻译功能")
+    Llama = None
+    llama_cpp_available = False
+
 class Translator:
     def __init__(self, model_path=None):
         self.model = None
         self.model_path = model_path
         self.is_ready = False
         self.model_name = ""
+        self.llama_cpp_available = llama_cpp_available
         
     def load_model(self, model_path=None):
         """加载模型"""
+        if not self.llama_cpp_available:
+            logger.error("llama-cpp-python库未找到，无法加载模型")
+            return False
+            
         if model_path:
             self.model_path = model_path
         
@@ -41,6 +54,10 @@ class Translator:
     
     def translate(self, text, context="", terms=None):
         """执行翻译"""
+        if not self.llama_cpp_available:
+            logger.error("llama-cpp-python库未找到，无法执行翻译")
+            return ""
+            
         if not self.is_ready or not self.model:
             logger.error("模型未就绪，无法执行翻译")
             return ""