Track changes is the file journal

A freelance editor takes on a 90,000-word manuscript. The author wants to see every change. The editor wants to work in a plain text editor, not Word's revision UI.

The manuscript lives in a container. The editor opens it in the files service's built-in editor and works. Every save is journaled: the files service keeps a content-addressed snapshot of each revision, with a timestamp and the operation that produced it.

The author doesn't get a DOCX with red ink. They get three URLs. chapter-4.md?history lists every revision. chapter-4.md?diff&from_seq=12&to_seq=19 shows what changed across a week. chapter-4.md?at=2026-08-14T09:00:00Z reads the file as it was before the big cut.

No suggesting mode, no accept-all button, no "which version is this." Track changes stops being a mode you turn on and becomes a property of the disk.