feat: 增加URL上下文理解功能

本次提交引入了一项新功能，允许模型在对话中理解所提供URL的上下文。

主要变更：

- **配置**：新增了 `URL_CONTEXT_ENABLED` 和 `URL_CONTEXT_MODELS` 两个配置项，用于控制此功能的开关和支持的模型列表。
- **后端服务**：在 `gemini_chat_service`、`openai_chat_service` 和 `vertex_express_chat_service` 中，为支持的模型动态添加 `urlContext` 工具。
- **前端界面**：在配置编辑器页面增加了相应的UI控件，方便用户启用/禁用该功能并管理支持的模型列表。
- **文档**：更新了 `.env.example`、`README.md` 和 `README_ZH.md`，包含了新配置项的说明。

app/service/chat/gemini_chat_service.py

@@ -119,15 +119,32 @@ def _build_tools(model: str, payload: Dict[str, Any]) -> List[Dict[str, Any]]:
         tool["codeExecution"] = {}
     if model.endswith("-search"):
         tool["googleSearch"] = {}
-
+    
+    real_model = _get_real_model(model)
+    if real_model in settings.URL_CONTEXT_MODELS and settings.URL_CONTEXT_ENABLED:
+        tool["urlContext"] = {}
+        
     # 解决 "Tool use with function calling is unsupported" 问题
     if tool.get("functionDeclarations"):
         tool.pop("googleSearch", None)
         tool.pop("codeExecution", None)
+        tool.pop("urlContext", None)
 
     return [tool] if tool else []
 
 
+def _get_real_model(model: str) -> str:
+    if model.endswith("-search"):
+        model = model[:-7]
+    if model.endswith("-image"):
+        model = model[:-6]
+    if model.endswith("-non-thinking"):
+        model = model[:-13]
+    if "-search" in model and "-non-thinking" in model:
+        model = model[:-20]
+    return model
+
+
 def _get_safety_settings(model: str) -> List[Dict[str, str]]:
     """获取安全设置"""
     if model == "gemini-2.0-flash-exp":

app/service/chat/openai_chat_service.py

@@ -87,6 +87,10 @@ def _build_tools(
 
     if model.endswith("-search"):
         tool["googleSearch"] = {}
+        
+    real_model = _get_real_model(model)
+    if real_model in settings.URL_CONTEXT_MODELS and settings.URL_CONTEXT_ENABLED:
+        tool["urlContext"] = {}
 
     # 将 request 中的 tools 合并到 tools 中
     if request.tools:
@@ -126,10 +130,23 @@ def _build_tools(
     if tool.get("functionDeclarations"):
         tool.pop("googleSearch", None)
         tool.pop("codeExecution", None)
+        tool.pop("urlContext",None)
 
     return [tool] if tool else []
 
 
+def _get_real_model(model: str) -> str:
+    if model.endswith("-search"):
+        model = model[:-7]
+    if model.endswith("-image"):
+        model = model[:-6]
+    if model.endswith("-non-thinking"):
+        model = model[:-13]
+    if "-search" in model and "-non-thinking" in model:
+        model = model[:-20]
+    return model
+
+
 def _get_safety_settings(model: str) -> List[Dict[str, str]]:
     """获取安全设置"""
     # if (

app/service/chat/vertex_express_chat_service.py

@@ -97,15 +97,32 @@ def _build_tools(model: str, payload: Dict[str, Any]) -> List[Dict[str, Any]]:
         tool["codeExecution"] = {}
     if model.endswith("-search"):
         tool["googleSearch"] = {}
+        
+    real_model = _get_real_model(model)
+    if real_model in settings.URL_CONTEXT_MODELS and settings.URL_CONTEXT_ENABLED:
+        tool["urlContext"] = {}
 
     # 解决 "Tool use with function calling is unsupported" 问题
     if tool.get("functionDeclarations"):
         tool.pop("googleSearch", None)
         tool.pop("codeExecution", None)
+        tool.pop("urlContext", None)
 
     return [tool] if tool else []
 
 
+def _get_real_model(model: str) -> str:
+    if model.endswith("-search"):
+        model = model[:-7]
+    if model.endswith("-image"):
+        model = model[:-6]
+    if model.endswith("-non-thinking"):
+        model = model[:-13]
+    if "-search" in model and "-non-thinking" in model:
+        model = model[:-20]
+    return model
+
+
 def _get_safety_settings(model: str) -> List[Dict[str, str]]:
     """获取安全设置"""
     if model == "gemini-2.0-flash-exp":