Your attention does not stop at the laptop lid. The mobile app is the third surface: an Android build that tracks where your phone time goes, carries the same shift with you, and settles it against the same day the browser and the desktop are writing to.
The mobile app inverts the extension's problem. In the browser Tabatha has to ask what you are doing, because a tab cannot tell it; on a phone the OS already knows, and the hard part is deciding what that means - forty minutes in a messaging app is either work or it is not, and only the shift you are on can say which. So the built half is almost entirely machinery: a native usage monitor, the categorizer ported from the desktop, and an offline-first sync stack that prefers your own network over the internet. The planned half is where the product actually becomes Tabatha rather than a screen-time report - above all the Focus Hub, which is the whole point and is not written yet.