Add archived to the frontend Project status type

[baranylcn]

The backend allows a project status of archived
(backend/app/schemas/project.py), but the frontend Project type only lists
'active' | 'completed' | 'failed'. An archived project therefore falls through
the status-style maps and is shown as "active".

Fix: add 'archived' to the Project.status union and give it a style
entry in the status maps.
Files: frontend/src/types.ts, frontend/src/pages/DashboardPage.tsx,
frontend/src/pages/ProjectsPage.tsx
Acceptance: an archived project renders its own status badge.