Expose disk_reclaim_service behind /api/v1/system/disk/reclaim: a
read-only report and a confirm-gated POST whose keys are re-validated
against a fresh scan server-side (safe candidates only — telemetry
stays CLI-only). ?wait=false runs it as a background job; both paths
are audit-logged.
The curated fix shows up where the problem is reported: a failing
disk.headroom doctor check and an alerting disk tile each offer
'Reclaim space', which previews measured candidates before handing
the run to Operations.
