Persist lookup data to disk and refresh on app foreground

- DataManager now persists lookup data (residence types, task categories,
  priorities, statuses, specialties, templates) to disk
- Loads cached lookups on app startup for faster launch
- iOS: Refresh lookups when app becomes active, refresh widget on background
- Android: Initialize DataManager in onCreate, already had onResume refresh
- Only send ETag if lookup data is actually in memory to avoid 304 with no data

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

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

iosApp/iosApp/iOSApp.swift

@@ -1,5 +1,6 @@
 import SwiftUI
 import ComposeApp
+import WidgetKit
 
 @main
 struct iOSApp: App {
@@ -44,6 +45,14 @@ struct iOSApp: App {
                     if newPhase == .active {
                         // Check and register device token when app becomes active
                         PushNotificationManager.shared.checkAndRegisterDeviceIfNeeded()
+
+                        // Refresh lookups/static data when app becomes active
+                        Task {
+                            _ = try? await APILayer.shared.initializeLookups()
+                        }
+                    } else if newPhase == .background {
+                        // Refresh widget when app goes to background
+                        WidgetCenter.shared.reloadAllTimelines()
                     }
                 }
                 // Import confirmation dialog