朱子纯 / test

- Sidebar 系统管理 now contains only 角色管理 / 菜单配置 / 操作日志
  (用户列表 and 系统模块配置 are accessed via mega-nav, not duplicated
  in the tree).
- MegaNav rebuilt as full-viewport dark layout per prototype: dark
  topbar with highlighted 全部导航 chip, 150px left rail of categories
  (active = accent + white left border), right grid of category columns
  with bordered titles and muted/featured items.
- MEGA_COLUMNS expanded to 8 columns matching prototype 系统设置
  (期初设置 / 用户管理 / 系统参数 / 计算方案 / 日志 / 开发平台 /
  API对接管理 / 系统模块).

Per docs/04 production stack: Vite + React 18 + TypeScript + AntD 5 +
Redux Toolkit + React Router v6 + Axios. Theme tokens copied from
prototype/XLY-ERP.html so density, colors, and layout match. Pages:
Login, Home, UserList, UserDetail, ModuleConfig — wired to existing
endpoints (/api/usr/auth/login, /api/usr/users, /api/mod/modules).
Backend-unsupported fields (user permission grid, 18 module fields,
iStaffId picker) hidden per scope. Sidebar/MegaNav remain static
reference data; dashboard stats hardcoded (no endpoint).