refactor: 移除多租户相关代码，重构为单租户架构

此次提交进行了大规模的架构重构：
1.  移除所有平台租户相关模块和代码，包括租户管理、套餐、订单、发票等功能
2.  将菜单模块从platform迁移到system模块，统一系统功能入口
3.  移除租户隔离相关的模型混入、中间件和配置
4.  简化文件上传、SSE事件总线、定时任务等模块的租户逻辑
5.  重构所有业务schema和模型，移除租户相关字段和关联
6.  清理初始化脚本、模板和常量中的租户相关代码
7.  简化认证和权限控制逻辑，移除数据范围检查相关代码

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

@@ -4,8 +4,6 @@ from typing import Annotated
 
 from fastapi import APIRouter, BackgroundTasks, Body, Depends, Path, Query, Request, status
 from fastapi.responses import JSONResponse, RedirectResponse
-from fastapi_cache import FastAPICache
-from fastapi_cache.decorator import cache
 from redis.asyncio.client import Redis
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -31,78 +29,26 @@ from .oauth_service import (
 )
 from .schema import (
     CaptchaOutSchema,
-    EnterPlatformOutSchema,
-    ImpersonateOutSchema,
-    ImpersonateSchema,
-    LoginWithTenantsSchema,
-    SelectTenantOutSchema,
-    SelectTenantSchema,
+    LoginOutSchema,
     SliderCompleteOutSchema,
     SliderCompleteSchema,
-    TenantLookupOutSchema,
-    TenantOptionSchema,
-    TenantRegisterOutSchema,
-    TenantRegisterSchema,
 )
 from .service import (
     CaptchaService,
     LoginService,
-    TenantLookupService,
-    TenantRegisterService,
 )
 
 AuthRouter = APIRouter(route_class=OperationLogRoute, prefix="/auth", tags=["认证授权"])
 
-_AUTH_TENANTS_NS = "auth_tenants"
 
-
-@AuthRouter.get("/tenant/{code}", summary="通过编码查询租户", response_model=ResponseSchema[TenantLookupOutSchema])
-async def lookup_tenant_controller(
-    db: Annotated[AsyncSession, Depends(db_getter)],
-    code: Annotated[str, Path(description="租户编码")],
-) -> JSONResponse:
-    """根据租户编码查询租户信息（用于登录页自动加载租户品牌配置）"""
-    data = await TenantLookupService.lookup_by_code(db=db, code=code)
-    return SuccessResponse(data=data, msg="查询成功")
-
-
-@AuthRouter.get("/tenant-by-domain", summary="通过域名查询租户", response_model=ResponseSchema[TenantLookupOutSchema])
-async def lookup_tenant_by_domain_controller(
-    db: Annotated[AsyncSession, Depends(db_getter)],
-    domain: Annotated[str, Query(description="域名（如 tenant.example.com）")],
-) -> JSONResponse:
-    """根据域名查询租户信息（用于登录页通过访问域名自动识别租户品牌）"""
-    data = await TenantLookupService.lookup_by_domain(db=db, domain=domain)
-    return SuccessResponse(data=data, msg="查询成功")
-
-
-@AuthRouter.get("/tenant-options", summary="获取所有租户选项（登录页下拉选择）", response_model=ResponseSchema[list[TenantOptionSchema]])
-async def get_tenant_options_controller(
-    db: Annotated[AsyncSession, Depends(db_getter)],
-) -> JSONResponse:
-    """获取所有活跃租户下拉选项"""
-    data = await TenantLookupService.list_options(db=db)
-    return SuccessResponse(data=data, msg="查询成功")
-
-
-@AuthRouter.get("/tenant-search", summary="搜索租户（按编码/名称模糊匹配）", response_model=ResponseSchema[list[TenantOptionSchema]])
-async def search_tenant_controller(
-    db: Annotated[AsyncSession, Depends(db_getter)],
-    q: Annotated[str, Query(description="搜索关键字")],
-) -> JSONResponse:
-    """模糊搜索租户"""
-    data = await TenantLookupService.search(db=db, q=q)
-    return SuccessResponse(data=data, msg="查询成功")
-
-
-@AuthRouter.post("/login", summary="登录", response_model=LoginWithTenantsSchema)
+@AuthRouter.post("/login", summary="登录", response_model=LoginOutSchema)
 async def login_for_access_token_controller(
     request: Request,
     background_tasks: BackgroundTasks,
     redis: Annotated[Redis, Depends(redis_getter)],
     db: Annotated[AsyncSession, Depends(db_getter)],
     login_form: Annotated[CustomOAuth2PasswordRequestForm, Depends()],
-) -> JSONResponse | LoginWithTenantsSchema:
+) -> JSONResponse | LoginOutSchema:
     login_result = await LoginService.authenticate_user(request=request, redis=redis, login_form=login_form, db=db, background_tasks=background_tasks)
 
     logger.info(f"用户{login_form.username}登录成功")
@@ -150,55 +96,6 @@ async def logout_controller(
     return ErrorResponse(msg="退出失败")
 
 
-@AuthRouter.post("/select-tenant", summary="选择租户", response_model=ResponseSchema[SelectTenantOutSchema], dependencies=[Depends(get_current_user)])
-async def select_tenant_controller(
-    request: Request,
-    auth: Annotated[AuthSchema, Depends(get_current_user)],
-    redis: Annotated[Redis, Depends(redis_getter)],
-    db: Annotated[AsyncSession, Depends(db_getter)],
-    data: Annotated[SelectTenantSchema, Body(description="租户选择参数")],
-) -> JSONResponse:
-    result = await LoginService(auth, db).select_tenant(request=request, redis=redis, tenant_id=data.tenant_id)
-    await FastAPICache.clear(namespace=_AUTH_TENANTS_NS)
-    return SuccessResponse(data=result, msg="租户切换成功")
-
-
-@AuthRouter.post("/enter-platform", summary="进入平台管理模式", response_model=ResponseSchema[EnterPlatformOutSchema], dependencies=[Depends(get_current_user)])
-async def enter_platform_controller(
-    request: Request,
-    auth: Annotated[AuthSchema, Depends(get_current_user)],
-    redis: Annotated[Redis, Depends(redis_getter)],
-    db: Annotated[AsyncSession, Depends(db_getter)],
-) -> JSONResponse:
-    result = await LoginService(auth, db).enter_platform(request=request, redis=redis)
-    await FastAPICache.clear(namespace=_AUTH_TENANTS_NS)
-    return SuccessResponse(data=result, msg="已返回平台管理模式")
-
-
-@AuthRouter.get("/tenants", summary="获取可选租户列表", response_model=ResponseSchema[list[TenantOptionSchema]], dependencies=[Depends(get_current_user)])
-@cache(expire=120, namespace=_AUTH_TENANTS_NS)
-async def get_user_tenants_controller(
-    auth: Annotated[AuthSchema, Depends(get_current_user)],
-    db: Annotated[AsyncSession, Depends(db_getter)],
-) -> JSONResponse:
-    service = LoginService(auth, db)
-    tenants = await service.get_user_tenants()
-    return SuccessResponse(data=tenants, msg="获取租户列表成功")
-
-
-@AuthRouter.post("/impersonate", summary="平台管理员代签入", response_model=ResponseSchema[ImpersonateOutSchema], dependencies=[Depends(get_current_user)])
-async def impersonate_controller(
-    request: Request,
-    auth: Annotated[AuthSchema, Depends(get_current_user)],
-    redis: Annotated[Redis, Depends(redis_getter)],
-    db: Annotated[AsyncSession, Depends(db_getter)],
-    data: Annotated[ImpersonateSchema, Body(description="代签入参数")],
-) -> JSONResponse:
-    result = await LoginService(auth, db).impersonate(request=request, redis=redis, tenant_id=data.tenant_id)
-    await FastAPICache.clear(namespace=_AUTH_TENANTS_NS)
-    return SuccessResponse(data=result, msg="代签入成功")
-
-
 @AuthRouter.get("/oauth/{provider}/login", summary="第三方OAuth跳转")
 async def oauth_login_redirect_controller(
     request: Request,
@@ -281,19 +178,3 @@ async def oauth_callback_controller(
     except CustomException as e:
         fe = await resolve_frontend()
         return RedirectContentResponse(url=oauth_service_error_redirect(fe, e.msg), status_code=302)
-
-
-@AuthRouter.post("/tenant/register", status_code=status.HTTP_201_CREATED, summary="租户自助注册", response_model=ResponseSchema[TenantRegisterOutSchema])
-async def tenant_register_controller(
-    db: Annotated[AsyncSession, Depends(db_getter)],
-    data: Annotated[TenantRegisterSchema, Body(description="租户注册参数")],
-) -> JSONResponse:
-    result = await TenantRegisterService.register(
-        db=db,
-        username=data.username,
-        password=data.password,
-        email=data.email,
-        tenant_name=data.tenant_name,
-    )
-    logger.info(f"新租户注册: username={data.username} tenant={result.tenant_name}")
-    return SuccessResponse(data=result, msg=result.message)