Fix 8 audit items: remove force-unwraps, improve accessibility and concurrency

- Replace force-unwrap HK types with modern HKQuantityType(_:) initializer
- Replace Calendar.date force-unwraps with guard/let in HealthService, HeaderPercView, MoodStreakActivity, DayViewViewModel, MonthTotalTemplate
- Extract DayViewViewModel.countEntries into testable static method with safe flatMap
- Replace DispatchQueue.main.asyncAfter with Task.sleep in CelebrationAnimations
- Add .minimumScaleFactor(0.5) to SmallRollUpHeaderView for Dynamic Type
- Add VoiceOver accessibility labels to HeaderPercView mood percentages
- Fix @testable import iFeel → Feels in Tests_iOS.swift
- Add 4 unit tests for countEntries (TDD)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Shared/Views/SmallRollUpHeaderView.swift

@@ -43,6 +43,7 @@ struct SmallRollUpHeaderView: View {
                     .font(.title2)
                     .fontWeight(.bold)
                     .lineLimit(1)
+                    .minimumScaleFactor(0.5)
                     .foregroundColor(moodTint.color(forMood: model.mood))
                     .frame(maxWidth: .infinity, alignment: .center)
             }