- Due-filter schedules: daily always, fixed days by weekday, one-offs on
their date; rest days get an empty state
- Workouts with no due schedule row (ad hoc or off-day starts) now render
as their own board rows
- The + sheet is now "New Workout" with a "When" picker; "Now" (offered
when adding on today) skips the schedule and starts the workout directly
- Remove the times-per-week scheduling mode everywhere (enum, document,
entity, mappers, planner, seeds, tests)