Workout streak: lifetime tally that only grows (never resets)

Per user model: the workout count should reflect every workout achieved and
never break. Replaces the consecutive/weekly-goal streak with a simple count
of distinct workout days (totalAchievedWorkoutDays). A below-goal week (4/5)
and a full week (5/5) both count fully (=9); a missed day or blank week never
reduces it; duplicate HealthKit days count once.

- ExerciseModels: streakDays = Set(workoutDates).count
- StreakLogicTests: retargeted to tally semantics (4/5+5/5=9, blank-week,
  duplicates, skipped-day, empty)
- SettingsView: goal caption no longer claims the streak can be lost

NOTE: not built/tested locally — CLI xcodebuild wedges on actool via the
broken CoreSimulator daemon (missing sim runtimes, machine-wide). Verify in
Xcode GUI (prefs now fixed) or on device.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

KisaniCal/Models/ExerciseModels.swift

@@ -249,50 +249,17 @@ class WorkoutViewModel: ObservableObject {
     @Published var restTimerTotal: Int = 0
     @Published var sessionStartDate: Date? = nil
 
-    /// Weekly-goal streak, per the Settings promise: "Reach your goal every week
-    /// to maintain your streak." Counts WORKOUT DAYS across consecutive kept weeks,
-    /// so rest days never break it and one skipped day within the goal doesn't
-    /// reset it. The current (in-progress) week never breaks the chain.
+    /// Lifetime tally of workout days achieved. Per the user's model this only ever
+    /// grows — a missed day, an off week, even a fully-blank week never reduce it.
+    /// A 4/5 week still contributes its 4; there is no "break." Not a consecutive
+    /// streak: it's the sum of everything you've actually done.
     var streakDays: Int {
-        let goal = UserDefaults.standard.object(forKey: "streakGoal") as? Int ?? 5
-        return Self.weeklyGoalStreak(workoutDates: Set(workoutDates),
-                                     scheduledDayCount: schedule.count,
-                                     goal: goal,
-                                     today: Date(),
-                                     calendar: Calendar.current)
+        Self.totalAchievedWorkoutDays(workoutDates)
     }
 
-    /// Pure streak math (unit-tested in StreakLogicTests).
-    /// - A past week is "kept" when its workout days ≥ min(goal, scheduled days).
-    /// - Streak = total workout days over the current week plus consecutive kept weeks.
-    static func weeklyGoalStreak(workoutDates: Set<String>,
-                                 scheduledDayCount: Int,
-                                 goal: Int,
-                                 today: Date,
-                                 calendar cal: Calendar) -> Int {
-        let fmt = DateFormatter(); fmt.dateFormat = "yyyy-MM-dd"
-        let target = scheduledDayCount > 0 ? min(max(goal, 1), scheduledDayCount) : max(goal, 1)
-
-        func daysDone(inWeekOf ref: Date) -> Int {
-            guard let week = cal.dateInterval(of: .weekOfYear, for: ref) else { return 0 }
-            var n = 0, d = week.start
-            while d < week.end {
-                if workoutDates.contains(fmt.string(from: d)) { n += 1 }
-                d = cal.date(byAdding: .day, value: 1, to: d)!
-            }
-            return n
-        }
-
-        var streak = daysDone(inWeekOf: today)   // current week: always counts, never breaks
-        var ref = today
-        for _ in 0..<520 {                       // walk back up to 10 years
-            guard let prev = cal.date(byAdding: .weekOfYear, value: -1, to: ref) else { break }
-            let done = daysDone(inWeekOf: prev)
-            guard done >= target else { break }
-            streak += done
-            ref = prev
-        }
-        return streak
+    /// Count of distinct workout days ever logged (unit-tested in StreakLogicTests).
+    static func totalAchievedWorkoutDays(_ workoutDates: [String]) -> Int {
+        Set(workoutDates).count
     }
 
     private let iso: DateFormatter = {