I'm working on an open source tool which is designed to be a zero config right click context menu with a two entries, "snapshot" and "restore". When you are of

I'm working on an open source tool which is designed to be a zero config right click context menu with a two entries, "snapshot" and "restore". When you are offline or online it works with a single click, then syncs to a server once internet is restored. It never deletes old versions, you always have the whole history. It also is encrypted client side and has data de-duplication. (The deduplication means you can keep snapshotting directories on a timer, and only changes are uploaded) It is not exactly what you described, but I can ping you when it is ready for people to test.