Fix 7 data mutation layer risks identified in audit

- save()/saveAndRunDataListeners() now return @discardableResult Bool;
  listeners only fire on successful save
- MoodLogger.updateMood() now recalculates streak, updates Live Activity,
  and notifies watch (was missing these side effects)
- CSV import uses new addBatch()/importMoods() for O(1) side effects
  instead of O(n) per-row widget reloads and streak calcs
- Foreground task ordering: fillInMissingDates() now runs before
  removeDuplicates() so backfill-created duplicates are caught same cycle
- WidgetMoodSaver deletes ALL entries for date (was fetchLimit=1, leaving
  CloudKit sync duplicates behind)
- cleanupPhotoIfNeeded logs warning on failed photo deletion instead of
  silently orphaning files

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

Shared/MoodLogger.swift

@@ -102,6 +102,110 @@ final class MoodLogger {
         markSideEffectsApplied(for: date)
     }
 
+    /// Delete a mood entry for a specific date with all associated cleanup.
+    /// Replaces the entry with a .missing placeholder and cleans up HealthKit/Live Activity state.
+    ///
+    /// - Parameter date: The date of the entry to delete
+    func deleteMood(forDate date: Date) {
+        // 1. Delete all entries for this date and replace with missing placeholder
+        DataController.shared.deleteAllEntries(forDate: date)
+        DataController.shared.add(mood: .missing, forDate: date, entryType: .filledInMissing)
+
+        Self.logger.info("Deleted mood entry for \(date)")
+
+        // 2. Delete HealthKit entry if enabled and user has access
+        let healthKitEnabled = GroupUserDefaults.groupDefaults.bool(forKey: UserDefaultsStore.Keys.healthKitEnabled.rawValue)
+        let hasAccess = !IAPManager.shared.shouldShowPaywall
+        if healthKitEnabled && hasAccess {
+            Task {
+                try? await HealthKitManager.shared.deleteMood(for: date)
+            }
+        }
+
+        // 3. Recalculate streak and update Live Activity
+        let streak = calculateCurrentStreak()
+        LiveActivityManager.shared.updateActivity(streak: streak, mood: .missing)
+        LiveActivityScheduler.shared.invalidateCache()
+        LiveActivityScheduler.shared.scheduleBasedOnCurrentTime()
+
+        // 4. Reload widgets
+        WidgetCenter.shared.reloadAllTimelines()
+
+        // 5. Notify watch to refresh
+        WatchConnectivityManager.shared.notifyWatchToReload()
+    }
+
+    /// Delete all mood data with full cleanup of HealthKit and Live Activity state.
+    /// Used when user clears all data from settings.
+    func deleteAllData() {
+        // 1. Clear all entries from the database
+        DataController.shared.clearDB()
+
+        Self.logger.info("Cleared all mood data")
+
+        // 2. Delete all HealthKit entries if enabled and user has access
+        let healthKitEnabled = GroupUserDefaults.groupDefaults.bool(forKey: UserDefaultsStore.Keys.healthKitEnabled.rawValue)
+        let hasAccess = !IAPManager.shared.shouldShowPaywall
+        if healthKitEnabled && hasAccess {
+            Task {
+                try? await HealthKitManager.shared.deleteAllMoods()
+            }
+        }
+
+        // 3. End all Live Activities
+        Task {
+            await LiveActivityManager.shared.endAllActivities()
+        }
+        LiveActivityScheduler.shared.invalidateCache()
+
+        // 4. Reload widgets
+        WidgetCenter.shared.reloadAllTimelines()
+
+        // 5. Notify watch to refresh
+        WatchConnectivityManager.shared.notifyWatchToReload()
+    }
+
+    /// Update an existing mood entry with all associated side effects.
+    /// Centralizes the update logic that was previously split between ViewModel and DataController.
+    ///
+    /// - Parameters:
+    ///   - entryDate: The date of the entry to update
+    ///   - mood: The new mood value
+    /// - Returns: Whether the update was successful
+    @discardableResult
+    func updateMood(entryDate: Date, withMood mood: Mood) -> Bool {
+        let success = DataController.shared.update(entryDate: entryDate, withMood: mood)
+        guard success else {
+            Self.logger.error("Failed to update mood entry for \(entryDate)")
+            return false
+        }
+
+        // Skip side effects for placeholder/missing moods
+        guard mood != .missing && mood != .placeholder else { return true }
+
+        // Sync to HealthKit if enabled and user has full access
+        let healthKitEnabled = GroupUserDefaults.groupDefaults.bool(forKey: UserDefaultsStore.Keys.healthKitEnabled.rawValue)
+        let hasAccess = !IAPManager.shared.shouldShowPaywall
+        if healthKitEnabled && hasAccess {
+            Task {
+                try? await HealthKitManager.shared.saveMood(mood, for: entryDate)
+            }
+        }
+
+        // Reload widgets
+        WidgetCenter.shared.reloadAllTimelines()
+
+        // Recalculate streak and update Live Activity
+        let streak = calculateCurrentStreak()
+        LiveActivityManager.shared.updateActivity(streak: streak, mood: mood)
+        LiveActivityScheduler.shared.invalidateCache()
+
+        // Notify watch to refresh
+        WatchConnectivityManager.shared.notifyWatchToReload()
+
+        return true
+    }
+
     /// Check for and process any pending side effects from widget/extension votes.
     /// Call this when the app becomes active to ensure all side effects are applied.
     func processPendingSideEffects() {
@@ -127,6 +231,19 @@ final class MoodLogger {
         applySideEffects(mood: entry.mood, for: entry.forDate)
     }
 
+    /// Import mood entries in batch with a single round of side effects.
+    /// Used for CSV import to avoid O(n) widget reloads, streak calcs, etc.
+    func importMoods(_ entries: [(mood: Mood, date: Date, entryType: EntryType)]) {
+        guard !entries.isEmpty else { return }
+
+        DataController.shared.addBatch(entries: entries)
+
+        // Single round of side effects
+        WidgetCenter.shared.reloadAllTimelines()
+        WatchConnectivityManager.shared.notifyWatchToReload()
+        LiveActivityScheduler.shared.invalidateCache()
+    }
+
     // MARK: - Side Effects Tracking
 
     /// Mark that side effects have been applied for a given date