- add `createAccountSetup`, `verifyAccountSetupToken`, `deleteAccountSetupToken` to verifications core
- add `completeAccountSetup` function to auth core for password creation on invite
- add `InvitationEmail` template for sending invite links
- add `SetupAccountPage` client page for invited users to set their password
- add `UserCreateModal` admin component to invite new users
- wire invitation action and API endpoint in auth feature
- update admin `UsersPage` to include user creation modal
- update auth and admin README docs
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