- Add viewer role to backend enum + Alembic migration
- SSO auto-provisioned users now get viewer (lowest privilege) by default
- Wire admin/users page to real API (replace mock data), with add/edit/deactivate
- Fix frontend UserRole enum to match backend (TM_MANAGER, REVIEWER)
- Replace hardcoded mock user in Sidebar with real auth, filter admin-only nav items, wire logout
- Add seed script to set default admins (daveporter, vadymsamoilenko)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>