feat : 推理层增加 vLLM 风格工具调用解析

- 新增 BaseToolParser 抽象基类，定义 feed/parse_complete 流式接口
- 新增 SimpleJsonToolParser，解析 {"name":"...","arguments":{...}} 格式
- 新增 ToolParserFactory，基于 BaseFactory 实现可插拔注册
- 集成 parser 到 OpenAIResponseBuilder，支持流式/非流式工具调用
- 扩展 ChatMessage 和 ChatCompletionRequest，增加 tools/tool_choice 字段
- 重构 format_chunk 接口，传入累积文本支持全量重新解析
- 新增 74 个单元测试，覆盖扫描/查找/流式解析/完整解析/工厂

astrai/inference/api/server.py

@@ -32,7 +32,20 @@ _app_instance: Optional[FastAPI] = None
 
 class ChatMessage(BaseModel):
     role: str
-    content: str
+    content: Optional[str] = None
+    tool_calls: Optional[List[Dict[str, Any]]] = None
+    tool_call_id: Optional[str] = None
+
+
+class FunctionDef(BaseModel):
+    name: str
+    description: Optional[str] = None
+    parameters: Optional[Dict[str, Any]] = None
+
+
+class ToolDef(BaseModel):
+    type: str = "function"
+    function: FunctionDef
 
 
 class ChatCompletionRequest(BaseModel):
@@ -51,6 +64,8 @@ class ChatCompletionRequest(BaseModel):
     frequency_penalty: Optional[float] = Field(default=0.0, ge=-2.0, le=2.0)
     logit_bias: Optional[Dict[int, float]] = None
     user: Optional[str] = None
+    tools: Optional[List[ToolDef]] = None
+    tool_choice: Optional[Union[str, Dict[str, Any]]] = "auto"
 
 
 class AnthropicMessage(BaseModel):