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/core/config.py

@@ -110,6 +110,11 @@ class Settings(BaseSettings):
     LINGXI_APP_SECRET: str = ""
     LINGXI_AGENT_ID: str = ""  # 创建灵犀后写入
 
+    # 人参果飞书应用配置（独立 WS 连接，路由到 AI学习助手 Agent — KG+RAG理想版）
+    RENSHENGUO_APP_ID: str = ""
+    RENSHENGUO_APP_SECRET: str = ""
+    RENSHENGUO_AGENT_ID: str = ""  # 创建 AI学习助手 后写入
+
     class Config:
         env_file = str(_ENV_PATH)
         case_sensitive = True