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/Persisence/DataController.swift

@@ -22,7 +22,8 @@ final class DataController: ObservableObject {
 
 
     // Listeners for data changes (keeping existing pattern)
-    private var editedDataClosure = [() -> Void]()
+    typealias DataListenerToken = UUID
+    private var dataListeners: [DataListenerToken: () -> Void] = [:]
 
     // Computed properties for earliest/latest entries
     var earliestEntry: MoodEntryModel? {
@@ -48,15 +49,22 @@ final class DataController: ObservableObject {
 
     // MARK: - Listener Management
 
-    func addNewDataListener(closure: @escaping (() -> Void)) {
-        editedDataClosure.append(closure)
+    @discardableResult
+    func addNewDataListener(closure: @escaping (() -> Void)) -> DataListenerToken {
+        let token = DataListenerToken()
+        dataListeners[token] = closure
+        return token
+    }
+
+    func removeDataListener(token: DataListenerToken) {
+        dataListeners.removeValue(forKey: token)
     }
 
     @discardableResult
     func saveAndRunDataListeners() -> Bool {
         let success = save()
         if success {
-            for closure in editedDataClosure {
+            for closure in dataListeners.values {
                 closure()
             }
         }
@@ -91,7 +99,7 @@ final class DataController: ObservableObject {
         modelContext.rollback()
 
         // Notify listeners to re-fetch their data
-        for closure in editedDataClosure {
+        for closure in dataListeners.values {
             closure()
         }
 

Shared/Persisence/DataControllerProtocol.swift

@@ -77,8 +77,12 @@ protocol MoodDataPersisting {
     @discardableResult
     func saveAndRunDataListeners() -> Bool
 
-    /// Add a listener for data changes
-    func addNewDataListener(closure: @escaping (() -> Void))
+    /// Add a listener for data changes, returns a token for removal
+    @discardableResult
+    func addNewDataListener(closure: @escaping (() -> Void)) -> DataController.DataListenerToken
+
+    /// Remove a previously registered data listener
+    func removeDataListener(token: DataController.DataListenerToken)
 }
 
 /// Combined protocol for full data controller functionality