The single-user release — phase 1 of the roadmap.
- Custom Office-style ribbon: Home, Insert, Formulas, Data, View, Review tabs.
- Formula bar with editable Name Box.
- Status bar: SUM / AVG / COUNT / MIN / MAX, zoom, sheet tabs.
- Full xlsx / ods / csv / tsv open + save in a Web Worker.
- All major Excel keyboard shortcuts in the first sweep.
- Initial Playwright e2e harness gating the surface.