Fix 25 audit issues: memory leaks, concurrency, performance, accessibility

Address findings from comprehensive audit across 5 workstreams:

- Memory: Token-based DataController listeners (prevent closure leaks),
  static DateFormatters, ImageCache observer cleanup, MotionManager
  reference counting, FoundationModels dedup guard
- Concurrency: Replace Task.detached with Task in FeelsApp (preserve
  MainActor isolation), wrap WatchConnectivity handler in MainActor
- Performance: Cache sortedGroupedData in DayViewViewModel, cache demo
  data in MonthView/YearView, remove broken ReduceMotionModifier
- Accessibility: VoiceOver support for LockScreen, DemoHeatmapCell
  labels, MonthCard button labels, InsightsView header traits,
  Smart Invert protection on neon headers

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

Shared/Services/FoundationModelsInsightService.swift

@@ -47,6 +47,7 @@ class FoundationModelsInsightService: ObservableObject {
 
     private var cachedInsights: [String: (insights: [Insight], timestamp: Date)] = [:]
     private let cacheValidityDuration: TimeInterval = 3600 // 1 hour
+    private var inProgressPeriods: Set<String> = []
 
     // MARK: - Initialization
 
@@ -199,6 +200,14 @@ class FoundationModelsInsightService: ObservableObject {
             return cached.insights
         }
 
+        // Prevent duplicate concurrent generation for the same period
+        guard !inProgressPeriods.contains(periodName) else {
+            // Already generating for this period, wait for cache
+            return cachedInsights[periodName]?.insights ?? []
+        }
+        inProgressPeriods.insert(periodName)
+        defer { inProgressPeriods.remove(periodName) }
+
         guard isAvailable else {
             throw InsightGenerationError.modelUnavailable(reason: lastError?.localizedDescription ?? "Model not available")
         }

Shared/Services/ImageCache.swift

@@ -15,13 +15,15 @@ final class ImageCache {
     private let cache = NSCache<NSString, UIImage>()
     private let queue = DispatchQueue(label: "com.tt.feels.imagecache", qos: .userInitiated)
 
+    private var memoryWarningToken: NSObjectProtocol?
+
     private init() {
         // Configure cache limits
         cache.countLimit = 100 // Max 100 images
         cache.totalCostLimit = 50 * 1024 * 1024 // 50 MB max
 
         // Clear cache on memory warning
-        NotificationCenter.default.addObserver(
+        memoryWarningToken = NotificationCenter.default.addObserver(
             forName: UIApplication.didReceiveMemoryWarningNotification,
             object: nil,
             queue: .main
@@ -30,6 +32,12 @@ final class ImageCache {
         }
     }
 
+    deinit {
+        if let token = memoryWarningToken {
+            NotificationCenter.default.removeObserver(token)
+        }
+    }
+
     // MARK: - Public API
 
     /// Get image from cache

Shared/Services/WatchConnectivityManager.swift

@@ -153,35 +153,32 @@ extension WatchConnectivityManager: WCSessionDelegate {
     }
 
     private func handleReceivedMessage(_ message: [String: Any]) {
-        guard let action = message["action"] as? String else {
-            Self.logger.error("No action in message")
-            return
-        }
-
-        switch action {
-        case "logMood":
-            guard let moodRaw = message["mood"] as? Int,
-                  let mood = Mood(rawValue: moodRaw),
-                  let timestamp = message["date"] as? TimeInterval else {
-                Self.logger.error("Invalid mood message format")
+        Task { @MainActor in
+            guard let action = message["action"] as? String else {
+                Self.logger.error("No action in message")
                 return
             }
 
-            let date = Date(timeIntervalSince1970: timestamp)
-            Self.logger.info("Processing mood \(moodRaw) from watch for \(date)")
+            switch action {
+            case "logMood":
+                guard let moodRaw = message["mood"] as? Int,
+                      let mood = Mood(rawValue: moodRaw),
+                      let timestamp = message["date"] as? TimeInterval else {
+                    Self.logger.error("Invalid mood message format")
+                    return
+                }
 
-            Task { @MainActor in
+                let date = Date(timeIntervalSince1970: timestamp)
+                Self.logger.info("Processing mood \(moodRaw) from watch for \(date)")
                 MoodLogger.shared.logMood(mood, for: date, entryType: .watch)
-            }
 
-        case "reloadWidgets":
-            Self.logger.info("Received reloadWidgets from watch")
-            Task { @MainActor in
+            case "reloadWidgets":
+                Self.logger.info("Received reloadWidgets from watch")
                 WidgetCenter.shared.reloadAllTimelines()
-            }
 
-        default:
-            Self.logger.warning("Unknown action: \(action)")
+            default:
+                Self.logger.warning("Unknown action: \(action)")
+            }
         }
     }
     #endif