v2.1: 新增通知提醒功能和安全增强

功能:
- 通知提醒系统: 还款日提醒、逾期提醒、系统消息横幅、登录时通知
- 通知中心UI: 铃铛图标 + 下拉列表 + 未读徽章
- 定时任务: APScheduler 每小时检查即将到期的还款
- 邮件通知: SMTP 发送还款提醒和安全警告
- 异常登录通知: 3/5/10次失败触发网页和邮件通知

安全:
- 登录安全告警: 异常登录次数达到阈值时发送通知
- 密码重置链接: 一次性使用, 5分钟有效期
- 登录频率限制: IP级和账户级限制

技术:
- 后端: FastAPI + SQLAlchemy + PostgreSQL
- 前端: 纯 HTML/CSS/JS
- 部署: Docker Compose (新增 build 配置)

backend/app/core/deps.py

@@ -0,0 +1,31 @@
+from fastapi import Depends, HTTPException, status
+from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select
+from app.core.database import get_db
+from app.core.security import decode_token
+from app.models.models import User
+
+security = HTTPBearer()
+
+
+async def get_current_user(
+    credentials: HTTPAuthorizationCredentials = Depends(security),
+    db: AsyncSession = Depends(get_db),
+) -> User:
+    token = credentials.credentials
+    payload = decode_token(token)
+    if not payload or payload.get("type") != "access":
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid token")
+    user_id = int(payload["sub"])
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if not user or user.status == "disabled":
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="User not found or disabled")
+    return user
+
+
+async def require_admin(user: User = Depends(get_current_user)) -> User:
+    if user.role != "admin":
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Admin required")
+    return user