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>

scripts/startup/stop.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+# 低代码智能体平台停止脚本
+
+echo "🛑 停止低代码智能体平台服务..."
+
+docker-compose -f docker-compose.dev.yml down
+
+echo "✅ 服务已停止"