feat: 数据备份管理系统 v0.1.0

带 Web 操作界面的备份系统，支持：
- 数据源：MySQL 数据库（mysqldump）、服务器目录（tar.gz）
- 存储目标：本地目录、S3 兼容对象存储（MinIO/Ceph/AWS S3）
- 触发方式：手动 + Cron 定时调度（APScheduler）
- 备份还原：MySQL 库、目录
- JWT 登录认证 + Fernet 字段加密
- 保留策略：按数量 + 按天数双重清理

技术栈：FastAPI + SQLAlchemy 2 + APScheduler + aioboto3；
前端 Vite + React 18 + TypeScript + Ant Design 5 + Zustand。
Docker Compose 一键起。

Co-Authored-By: Claude <noreply@anthropic.com>

backend/app/api/auth.py

@@ -0,0 +1,39 @@
+"""认证 API。"""
+from fastapi import APIRouter, HTTPException, status
+
+from app.config import get_settings
+from app.deps import CurrentUser, DBSession
+from app.models.user import User
+from app.schemas.auth import (
+    ChangePasswordRequest,
+    LoginRequest,
+    MessageResponse,
+    TokenResponse,
+    UserOut,
+)
+from app.security import create_access_token, hash_password, verify_password
+
+router = APIRouter(prefix="/auth", tags=["auth"])
+
+
+@router.post("/login", response_model=TokenResponse)
+def login(payload: LoginRequest, db: DBSession) -> TokenResponse:
+    user = db.query(User).filter(User.username == payload.username).first()
+    if not user or not user.is_active or not verify_password(payload.password, user.password_hash):
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid credentials")
+    token = create_access_token(user.username, extra={"uid": user.id, "adm": user.is_admin})
+    return TokenResponse(access_token=token, expires_in=get_settings().JWT_EXPIRE_MINUTES * 60)
+
+
+@router.get("/me", response_model=UserOut)
+def me(user: CurrentUser) -> User:
+    return user
+
+
+@router.post("/change-password", response_model=MessageResponse)
+def change_password(payload: ChangePasswordRequest, user: CurrentUser, db: DBSession) -> MessageResponse:
+    if not verify_password(payload.old_password, user.password_hash):
+        raise HTTPException(status_code=400, detail="原密码错误")
+    user.password_hash = hash_password(payload.new_password)
+    db.commit()
+    return MessageResponse(message="Password updated")