智教助手平台：完整初始化

- 前端：Vue3 + TS + Element Plus，24 个页面路由（课件/组题/教案/动画/思维导图/作文批改/命题/课堂/资源/社区等）
- 后端：FastAPI + SQLAlchemy + SQLite，17 个路由模块，AI 服务层含降级模板
- AI：glm-5.x 推理模型已禁用思维链，确保输出真实内容
- 修复：ai_service 两处请求体注入 enable_thinking/thinking disabled
- 测试账号：13900999999 / test1234

backend/models/notification.py

@@ -0,0 +1,21 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, ForeignKey
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+from database import Base
+
+
+class Notification(Base):
+    """站内通知：评论/收藏/系统消息。"""
+    __tablename__ = "notifications"
+
+    id = Column(Integer, primary_key=True, index=True)
+    user_id = Column(Integer, ForeignKey("users.id"), nullable=False, index=True)
+    actor_id = Column(Integer, nullable=True)
+    ntype = Column(String(32), nullable=False, default="comment")
+    title = Column(String(200), nullable=False)
+    content = Column(String(500), default="")
+    link = Column(String(255), default="")
+    is_read = Column(Boolean, default=False)
+    created_at = Column(DateTime, server_default=func.now())
+
+    user = relationship("User", back_populates="notifications")