refactor: 移除多租户相关逻辑并清理冗余代码

本次提交完成以下主要变更：
1.  删除所有租户相关的初始化数据、配置和工具代码
2.  移除TicketModel的租户关联字段与校验逻辑
3.  重构菜单表名与关联外键，统一为sys_前缀
4.  为岗位、部门、工作流等模型添加唯一约束
5.  调整导入顺序与冗余代码，优化代码结构
6.  移除支付、PDF生成相关的依赖与工具类
7.  简化OpenAPI文档标签配置
8.  清理无效的枚举与冗余导入

backend/app/api/v1/module_system/auth/controller.py

@@ -2,14 +2,14 @@ import json
 import secrets
 from typing import Annotated
 
-from fastapi import APIRouter, BackgroundTasks, Body, Depends, Path, Query, Request, status
+from fastapi import APIRouter, BackgroundTasks, Body, Depends, Path, Query, Request
 from fastapi.responses import JSONResponse, RedirectResponse
 from redis.asyncio.client import Redis
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.common.response import ErrorResponse, RedirectContentResponse, ResponseSchema, SuccessResponse
 from app.config.setting import settings
-from app.core.base_schema import AuthSchema, JWTOutSchema
+from app.core.base_schema import JWTOutSchema
 from app.core.dependencies import db_getter, get_current_user, redis_getter
 from app.core.exceptions import CustomException
 from app.core.logger import logger