Admin can now toggle "OAuth-only (no password)" when creating a user.
These users have no password hash and authProvider set to 'none', so
they can only log in via an OAuth/SSO provider.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- GET/POST /api/admin/users — list and create users (admin only)
- PATCH/DELETE /api/admin/users/[id] — update role/reset password, delete user
- PUT /api/auth/password — change own password
All admin routes guarded by requireAdmin().
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
