Characterizes the 'back up phone -> delete locally -> must stay in cloud'
scenario across the real multi-cycle engine state (upload saves null remote
metadata; next sync reconciles), asserting per delete behavior:
- KEEP -> SKIP (cloud copy retained) — correct backup behavior
- ARCHIVE -> DELETE_REMOTE decision (engine moves to _Deleted/, preserved)
- MIRROR -> DELETE_REMOTE (cloud copy wiped) — footgun, and the current default
Also: upload-only never pulls a new remote file down; local edits still upload.
