Whats new implementation.

Wino.Core.Domain/Interfaces/IAppMigration.cs

@@ -0,0 +1,15 @@
+using System.Threading.Tasks;
+
+namespace Wino.Core.Domain.Interfaces;
+
+/// <summary>
+/// Represents a one-time app or data migration that runs when a user updates to a new version.
+/// </summary>
+public interface IAppMigration
+{
+    /// <summary>Gets the unique identifier for this migration, used to track completion in local settings.</summary>
+    string MigrationId { get; }
+
+    /// <summary>Executes the migration logic.</summary>
+    Task ExecuteAsync();
+}

Wino.Core.Domain/Interfaces/IDialogServiceBase.cs

@@ -5,6 +5,7 @@ using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Models.Accounts;
 using Wino.Core.Domain.Models.Common;
 using Wino.Core.Domain.Models.Printing;
+using Wino.Core.Domain.Models.Updates;
 
 namespace Wino.Core.Domain.Interfaces;
 
@@ -30,4 +31,10 @@ public interface IDialogServiceBase
     Task<List<SharedFile>> PickFilesAsync(params object[] typeFilters);
     Task<string> PickFilePathAsync(string saveFileName);
     Task<WebView2PrintSettingsModel> ShowPrintDialogAsync(WebView2PrintSettingsModel initialSettings = null);
+
+    /// <summary>
+    /// Presents the "What's New" dialog for the current version.
+    /// This dialog is undismissable and runs any pending migrations when the user clicks "Get Started".
+    /// </summary>
+    Task ShowWhatIsNewDialogAsync(UpdateNotes notes);
 }

Wino.Core.Domain/Interfaces/INotificationBuilder.cs

@@ -40,4 +40,10 @@ public interface INotificationBuilder
     /// Creates a calendar reminder toast for the specified calendar item.
     /// </summary>
     Task CreateCalendarReminderNotificationAsync(CalendarItem calendarItem, long reminderDurationInSeconds);
+
+    /// <summary>
+    /// Shows a notification that a migration is required for the new app version.
+    /// Synchronization is stopped and the user is prompted to open the app.
+    /// </summary>
+    void CreateMigrationRequiredNotification();
 }

Wino.Core.Domain/Interfaces/IUpdateManager.cs

@@ -0,0 +1,26 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Wino.Core.Domain.Models.Updates;
+
+namespace Wino.Core.Domain.Interfaces;
+
+public interface IUpdateManager
+{
+    /// <summary>Loads and parses the update notes for the current version from the bundled asset file.</summary>
+    Task<UpdateNotes> GetLatestUpdateNotesAsync();
+
+    /// <summary>Returns true if the current version's update notes have not yet been shown to the user.</summary>
+    bool ShouldShowUpdateNotes();
+
+    /// <summary>Stores a flag in local settings indicating the update notes for the current version have been seen.</summary>
+    void MarkUpdateNotesAsSeen();
+
+    /// <summary>Returns true if any registered migration has not yet been completed.</summary>
+    bool HasPendingMigrations();
+
+    /// <summary>Runs all pending migrations in order and marks each as completed in local settings.</summary>
+    Task RunPendingMigrationsAsync();
+
+    /// <summary>Registers migrations to be tracked and executed by this manager.</summary>
+    void RegisterMigrations(IEnumerable<IAppMigration> migrations);
+}