- add optional `permission` field to route definitions with type validation in `define.js`
- check `hasPermission()` in router after `requireAdmin()` and return 403 if denied
- document `permission` and `skipRateLimit` optional fields in api README
- load user permissions in `AdminPage.server.js` and pass them to client via `user` prop
- use `user.permissions` in `RolesPage` and `UsersPage` to conditionally render actions
- expose permission-gated API routes in `auth/api.js`
- add `ZEN_DEVKIT` env variable to enable/disable devkit
- add `isDevkitEnabled()` utility and export it from public api
- register devkit nav section and items conditionally when devkit is enabled
- add devkit route handling in admin page client and server
- add DevkitPage, ComponentsPage, and IconsPage client components
BREAKING CHANGE: sup config now derives entries from package.json#exports and a server/client glob instead of manual lists; module structure follows flat + barrel convention with .server.js/.client.js runtime suffixes