Adds a new card on the System tab that triggers the existing
POST /api/admin/trigger-import endpoint. Status is polled every 2 s
while RUNNING and stops automatically on DONE or FAILED.
IDLE/RUNNING/DONE/FAILED states each render distinct UI feedback.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Moves the system maintenance panel out of the old tab-based admin page
and into a dedicated route. Renders maintenance cards with spinner state
and success message on completion.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>