Add HealthKit backfill to sync all existing moods

When user enables HealthKit integration, automatically syncs all
previously recorded mood entries to Apple Health. Features:
- Progress tracking with visual indicator in Settings
- Batched saves with throttling to avoid overwhelming HealthKit
- Success/failure logging with EventLogger

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

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

Shared/HealthKitManager.swift

@@ -7,15 +7,21 @@
 
 import Foundation
 import HealthKit
+import os.log
 
 @MainActor
 class HealthKitManager: ObservableObject {
     static let shared = HealthKitManager()
 
     private let healthStore = HKHealthStore()
+    private let logger = Logger(subsystem: Bundle.main.bundleIdentifier ?? "com.tt.ifeel", category: "HealthKit")
 
     @Published var isAuthorized = false
     @Published var authorizationError: Error?
+    @Published var isSyncing = false
+    @Published var syncProgress: Double = 0
+    @Published var syncedCount: Int = 0
+    @Published var totalToSync: Int = 0
 
     // State of Mind sample type
     private var stateOfMindType: HKSampleType? {
@@ -80,6 +86,76 @@ class HealthKitManager: ObservableObject {
         try await healthStore.save(stateOfMind)
     }
 
+    // MARK: - Sync All Existing Moods to HealthKit
+
+    /// Syncs all existing mood entries from the app to HealthKit
+    /// Call this after HealthKit authorization is granted to backfill historical data
+    func syncAllMoods() async {
+        guard isHealthKitAvailable else {
+            logger.warning("HealthKit not available, skipping sync")
+            return
+        }
+
+        guard checkAuthorizationStatus() == .sharingAuthorized else {
+            logger.warning("HealthKit not authorized for sharing, skipping sync")
+            return
+        }
+
+        isSyncing = true
+        syncProgress = 0
+        syncedCount = 0
+
+        // Fetch all mood entries
+        let allEntries = DataController.shared.getData(
+            startDate: Date(timeIntervalSince1970: 0),
+            endDate: Date(),
+            includedDays: [1, 2, 3, 4, 5, 6, 7]
+        )
+
+        // Filter out missing and placeholder entries
+        let validEntries = allEntries.filter { entry in
+            entry.mood != .missing && entry.mood != .placeholder
+        }
+
+        totalToSync = validEntries.count
+        logger.info("Starting HealthKit sync for \(validEntries.count) mood entries")
+
+        guard totalToSync > 0 else {
+            logger.info("No mood entries to sync")
+            isSyncing = false
+            return
+        }
+
+        var successCount = 0
+        var failCount = 0
+
+        for (index, entry) in validEntries.enumerated() {
+            do {
+                try await saveMood(entry.mood, for: entry.forDate, note: entry.notes)
+                successCount += 1
+            } catch {
+                failCount += 1
+                logger.error("Failed to sync mood for \(entry.forDate): \(error.localizedDescription)")
+            }
+
+            syncedCount = index + 1
+            syncProgress = Double(syncedCount) / Double(totalToSync)
+
+            // Add a small delay to avoid overwhelming HealthKit
+            if index % 10 == 0 && index > 0 {
+                try? await Task.sleep(nanoseconds: 50_000_000) // 50ms
+            }
+        }
+
+        isSyncing = false
+        logger.info("HealthKit sync complete: \(successCount) succeeded, \(failCount) failed")
+        EventLogger.log(event: "healthkit_sync_complete", withData: [
+            "total": totalToSync,
+            "success": successCount,
+            "failed": failCount
+        ])
+    }
+
     // MARK: - Read Mood from HealthKit
 
     func fetchMoods(from startDate: Date, to endDate: Date) async throws -> [HKStateOfMind] {

Shared/Views/SettingsView/SettingsView.swift

@@ -238,6 +238,8 @@ struct SettingsContentView: View {
                                     // Request write permissions for State of Mind sync
                                     do {
                                         try await HealthKitManager.shared.requestAuthorization()
+                                        // Sync all existing moods to HealthKit
+                                        await HealthKitManager.shared.syncAllMoods()
                                     } catch {
                                         print("HealthKit write authorization failed: \(error)")
                                     }
@@ -259,6 +261,19 @@ struct SettingsContentView: View {
                 }
             }
             .padding()
+
+            // Show sync progress
+            if HealthKitManager.shared.isSyncing {
+                VStack(spacing: 8) {
+                    ProgressView(value: HealthKitManager.shared.syncProgress)
+                        .tint(.red)
+                    Text("Syncing moods to Health... \(HealthKitManager.shared.syncedCount)/\(HealthKitManager.shared.totalToSync)")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                }
+                .padding(.horizontal)
+                .padding(.bottom, 8)
+            }
         }
         .fixedSize(horizontal: false, vertical: true)
         .cornerRadius(Constants.viewsCornerRaidus, corners: [.topLeft, .topRight, .bottomLeft, .bottomRight])
@@ -708,6 +723,8 @@ struct SettingsView: View {
                                     // Request write permissions for State of Mind sync
                                     do {
                                         try await HealthKitManager.shared.requestAuthorization()
+                                        // Sync all existing moods to HealthKit
+                                        await HealthKitManager.shared.syncAllMoods()
                                     } catch {
                                         print("HealthKit write authorization failed: \(error)")
                                     }
@@ -729,6 +746,19 @@ struct SettingsView: View {
                 }
             }
             .padding()
+
+            // Show sync progress
+            if HealthKitManager.shared.isSyncing {
+                VStack(spacing: 8) {
+                    ProgressView(value: HealthKitManager.shared.syncProgress)
+                        .tint(.red)
+                    Text("Syncing moods to Health... \(HealthKitManager.shared.syncedCount)/\(HealthKitManager.shared.totalToSync)")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                }
+                .padding(.horizontal)
+                .padding(.bottom, 8)
+            }
         }
         .fixedSize(horizontal: false, vertical: true)
         .cornerRadius(Constants.viewsCornerRaidus, corners: [.topLeft, .topRight, .bottomLeft, .bottomRight])