Add comprehensive WCAG 2.1 AA accessibility support

- Add VoiceOver labels and hints to all voting layouts, settings, widgets,
  onboarding screens, and entry cells
- Add Reduce Motion support to button animations throughout the app
- Ensure 44x44pt minimum touch targets on widget mood buttons
- Enhance AccessibilityHelpers with Dynamic Type support, ScaledValue wrapper,
  and VoiceOver detection utilities
- Gate premium features (Insights, Month/Year views) behind subscription
- Update widgets to show subscription prompts for non-subscribers

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Shared/Onboarding/views/OnboardingDay.swift

@@ -127,6 +127,7 @@ struct DayOptionCard: View {
                         .font(.system(size: 20))
                         .foregroundColor(isSelected ? Color(hex: "4facfe") : .white)
                 }
+                .accessibilityHidden(true)
 
                 // Text
                 VStack(alignment: .leading, spacing: 3) {
@@ -152,6 +153,7 @@ struct DayOptionCard: View {
                     Image(systemName: "checkmark.circle.fill")
                         .font(.system(size: 22))
                         .foregroundColor(Color(hex: "4facfe"))
+                        .accessibilityHidden(true)
                 }
             }
             .padding(.horizontal, 16)
@@ -163,6 +165,9 @@ struct DayOptionCard: View {
             )
         }
         .buttonStyle(.plain)
+        .accessibilityLabel("\(title), \(subtitle)")
+        .accessibilityHint(example)
+        .accessibilityAddTraits(isSelected ? [.isSelected] : [])
     }
 }