Three tests broke when the Admin/User/Passthrough privilege model replaced
the old admin/user/guest hierarchy in PR-3.
- user-management: tighten heading locator to name='User Management' to avoid
strict mode violation; the settings layout now renders a second h1
('Settings') alongside the page content heading
- user-lifecycle: update audit trail assertion from 2 to 1; users are now
created with a role in a single API call so the backend does not emit a
user_update audit entry when STEP 2 sends the same role value as creation
- auth-fixtures: replace invalid role='guest' with role='passthrough' in the
guestUser fixture; the 'guest' role was removed in PR-3 and 'passthrough' is
the equivalent lowest-privilege role in the new model
Verified: all three previously-failing tests now pass locally.
- Implemented middleware to restrict access for passthrough users in management routes.
- Added unit tests for management access requirements based on user roles.
- Updated user model tests to include passthrough role validation.
- Enhanced frontend user management to support passthrough role in invite modal.
- Created end-to-end tests for passthrough user access restrictions and navigation visibility.
- Verified self-service profile management for admins and regular users.
Bump workspace and backend module to Go 1.26 to satisfy module toolchain requirements and allow dependency tooling (Renovate) to run. Regenerated backend module checksums.