Show only the day's docket on the Today board and add ad hoc Now workouts

- 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)

Shared/Model/Documents.swift

@@ -376,7 +376,6 @@ struct ScheduleDocument: Codable, Sendable, Equatable, Identifiable {
     var goal: String?         // GoalKind raw value; nil = unassigned
     var recurrence: String    // ScheduleRecurrence raw value
     var weekdays: [Int]?      // Calendar weekday numbers 1 (Sun) – 7 (Sat); .fixedDays only
-    var timesPerWeek: Int?    // .frequency only
     var date: Date? = nil     // the one-off day; .once only
     var order: Int
     var createdAt: Date
@@ -394,9 +393,9 @@ extension ScheduleDocument {
     /// The recurrence, defaulting to `.daily` on an unknown raw value.
     var recurrenceEnum: ScheduleRecurrence { ScheduleRecurrence(rawValue: recurrence) ?? .daily }
 
-    /// Human-readable recurrence line ("Jul 12, 2026" / "Daily" / "Mon & Thu" / "2× per week").
+    /// Human-readable recurrence line ("Jul 12, 2026" / "Daily" / "Mon & Thu").
     var recurrenceSummary: String {
-        recurrenceEnum.summary(weekdays: weekdays, timesPerWeek: timesPerWeek, date: date)
+        recurrenceEnum.summary(weekdays: weekdays, date: date)
     }
 }