feat: 增强 core/agents 工具和 API

- 新增 loop.py Agent 运行循环
- 优化 memory.py 记忆模块
- 扩展 api/routes.py 接口
- 更新 tools 模块：builtin.py, manager.py, __init__.py
- 新增 .env.example 配置示例
- 更新 requirements.txt 依赖

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/agents/api/routes.py

@@ -20,7 +20,7 @@ class ChatRequest(BaseModel):
 
     Fields aligned with server/internal/service/agent_service.go::AgentChatRequest
     """
-    agent_id: int
+    agent_id: str  # 支持 UUID 字符串
     message: str
     user_id: int = 0
     session_id: str | None = None
@@ -37,7 +37,7 @@ class ChatResponse(BaseModel):
 
     Fields aligned with server/internal/service/agent_service.go::AgentChatResponse
     """
-    agent_id: int
+    agent_id: str  # 支持 UUID 字符串
     response: str
     tool_calls: list = []
     tokens_used: int = 0
@@ -209,7 +209,10 @@ async def chat_stream(request: ChatRequest):
     Yields:
         Streaming response chunks in SSE format
     """
+    logger.info(f"[chat_stream] Received request: agent_id={request.agent_id}, message={request.message[:50]}...")
+
     if _agent is None:
+        logger.error("[chat_stream] Agent not initialized!")
         raise HTTPException(status_code=500, detail="Agent not initialized")
 
     session_id = request.session_id or f"session_{request.agent_id}_{int(time.time())}"
@@ -217,6 +220,8 @@ async def chat_stream(request: ChatRequest):
     async def generate() -> AsyncGenerator[str, None]:
         """Generate streaming response."""
         try:
+            logger.info(f"[chat_stream] Starting stream for session: {session_id}")
+
             # Prepare kwargs for agent.chat()
             kwargs = {
                 "message": request.message,
@@ -225,28 +230,38 @@ async def chat_stream(request: ChatRequest):
 
             if request.model_id:
                 kwargs["model_id"] = request.model_id
+                logger.info(f"[chat_stream] Using model_id: {request.model_id}")
             if request.model_name:
                 kwargs["model_name"] = request.model_name
+                logger.info(f"[chat_stream] Using model_name: {request.model_name}")
             if request.model_provider:
                 kwargs["model_provider"] = request.model_provider
+                logger.info(f"[chat_stream] Using model_provider: {request.model_provider}")
             if request.api_key:
                 kwargs["api_key"] = request.api_key
+                logger.info(f"[chat_stream] Using api_key: {request.api_key[:10]}...")
             if request.base_url:
                 kwargs["base_url"] = request.base_url
+                logger.info(f"[chat_stream] Using base_url: {request.base_url}")
             if request.use_xbot:
                 kwargs["use_xbot"] = request.use_xbot
+                logger.info(f"[chat_stream] Using use_xbot: {request.use_xbot}")
 
             # Process with streaming
+            chunk_count = 0
             async for chunk in _agent.chat_stream(**kwargs):
-                # SSE format: "data: <json>\n\n"
-                yield f"data: {json.dumps(chunk)}\n\n"
+                chunk_count += 1
+                logger.info(f"[chat_stream] Yielding chunk {chunk_count}: {chunk}")
+                # SSE format: "data: <json>\n\n" - ensure_ascii=False to output UTF-8 characters directly
+                yield f"data: {json.dumps(chunk, ensure_ascii=False)}\n\n"
 
+            logger.info(f"[chat_stream] Stream complete, yielded {chunk_count} chunks")
             # Send final message
-            yield f"data: {json.dumps({'done': True, 'session_id': session_id})}\n\n"
+            yield f"data: {json.dumps({'done': True, 'session_id': session_id}, ensure_ascii=False)}\n\n"
 
         except Exception as e:
             logger.exception(f"Error in streaming chat: {e}")
-            yield f"data: {json.dumps({'error': str(e)})}\n\n"
+            yield f"data: {json.dumps({'error': str(e)}, ensure_ascii=False)}\n\n"
 
     from fastapi.responses import StreamingResponse