Shifts, rotations and weekly offs

A shift has a start, an end and the rules for late and early. Tick 24-hour shift for a shift that ends at the same time next day. Editing a shift asks Applies from and keeps a version history, so past days stay judged by the rules in force then.

1. Under Roster, build a rotation from steps: a shift (or OFF) for a number of days, up to 20 steps.
2. Pick the people, the date range (up to a year) and an optional stagger so not everyone is off on the same day.
3. Preview first. Conflicts and locked days are shown; Apply is enabled only when the preview is clean.

Applied rotations are ordinary roster rows — you can still change a single day by hand.

From an employee's roster drawer, set their own weekly-off days (and Saturday rule) from a date. An earlier open-ended pattern is closed the day before the new one starts.