* feat(system): multipart backup import via SAF picker — replace path-based import (issue #786) * fix(system): backup trigger sends required JSON body — 422 fix (BackupRequest contract) * fix(system): backup download waits for async archive + saves to Downloads * fix(system): curator min_idle_hours Double parse + single-flight backup download * fix(system): stream backup download to Downloads — @Streaming + chunked MediaStore write (OOM fix) --------- Co-authored-by: M57 <hy4ri@users.noreply.github.com>