- Interruption: failed mid-write leaves original intact (no truncation, no temp
leftover); a sync that drops after N files resumes cleanly on the next sync
with all content byte-intact (real network-drop simulation).
- SFTP: live round-trip test against an SFTP server (connect/upload-atomic/
list/download/overwrite/special-name/delete); skips if endpoint unreachable.
- Scheduling: WorkManager request builders map Wi-Fi-only -> UNMETERED,
charging-only -> requiresCharging, interval, input data, and tags correctly.
