feat: add AI学习助手 agent (KG+RAG ideal) and renshenguo feishu bot

- Add AI学习助手 agent creation script with all 39 tools, 3-layer KG+RAG memory
- Add renshenguo (人参果) feishu bot integration (app_service + ws_handler)
- Register renshenguo WS client in main.py startup
- Add RENSHENGUO_APP_ID / RENSHENGUO_APP_SECRET / RENSHENGUO_AGENT_ID config
- Reorganize docs from root into docs/ subdirectories
- Move startup scripts to scripts/startup/
- Various backend optimizations and tool improvements

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

backend/app/api/agents.py

@@ -1,7 +1,7 @@
 """
 Agent管理API
 """
-from fastapi import APIRouter, Depends, HTTPException, status, Query
+from fastapi import APIRouter, Depends, HTTPException, status, Query, Response
 from sqlalchemy.orm import Session
 from pydantic import BaseModel, Field
 from typing import List, Optional, Dict, Any
@@ -101,6 +101,7 @@ class AgentResponse(BaseModel):
 
 @router.get("", response_model=List[AgentResponse])
 async def get_agents(
+    response: Response,
     skip: int = Query(0, ge=0, description="跳过记录数"),
     limit: int = Query(100, ge=1, le=100, description="每页记录数"),
     search: Optional[str] = Query(None, description="搜索关键词（按名称或描述）"),
@@ -152,9 +153,12 @@ async def get_agents(
     if status:
         query = query.filter(Agent.status == status)
     
+    # 先获取总数（不带分页）
+    total_count = query.count()
+
     # 排序和分页
     agents = query.order_by(Agent.created_at.desc()).offset(skip).limit(limit).all()
-    
+
     # 转换为响应格式，确保user_id和日期时间字段正确处理
     result = []
     for agent in agents:
@@ -170,7 +174,9 @@ async def get_agents(
             "created_at": agent.created_at if agent.created_at else datetime.now(),
             "updated_at": agent.updated_at if agent.updated_at else datetime.now()
         })
-    
+
+    # 通过 X-Total-Count 响应头返回总数，前端借此正确分页
+    response.headers["X-Total-Count"] = str(total_count)
     return result