Most timers are good at counting and bad at billing. Span is built backwards from the invoice.
- A week as a grid of projects × days, filled in place, with one running timer at a time
- Rounding and rate live on the client, with a per-project override where reality demands it
- Invoice lines generated from tracked time, ready to hand over
- CSV export for everything else
- Three languages, light and dark themes, one Go binary with SQLite