Per-type test routines for 7 remote types (qbittorrent, prometheus via Grafana
gateway, alertmanager, jellyfin, authentik, ssh_tasks, nextcloud) + backups
(no test). Endpoint POST /api/services/test, no persistence, friendly error
translation (resolves qBit login #3 at UI layer). Frontend Test button + gate
Create/Save on pass with Save-anyway override. Stale-proposal correction:
jellyseerr is not in the registry (merged into jellyfin).
Developer