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/main.py

@@ -248,6 +248,13 @@ async def startup_event():
     except Exception as e:
         logger.error(f"灵犀长连接启动失败: {e}")
 
+    # 启动人参果飞书长连接（AI学习助手 — KG+RAG理想版）
+    try:
+        from app.services.renshenguo_ws_handler import start_ws_client as start_renshenguo_ws
+        asyncio.ensure_future(start_renshenguo_ws())
+    except Exception as e:
+        logger.error(f"人参果长连接启动失败: {e}")
+
 # 注册路由
 from app.api import auth, uploads, workflows, executions, websocket, execution_logs, data_sources, agents, platform_templates, model_configs, webhooks, template_market, batch_operations, collaboration, permissions, monitoring, alert_rules, node_test, node_templates, tools, agent_chat, agent_monitoring, knowledge_base, agent_schedules, notifications, feishu_bind, approval