feat(help): add offline guidance and resumable first-use setup (U14)

src/Duempelkas.Infrastructure/Services/SettingsService.cs

@@ -25,6 +25,14 @@ public class SettingsService : ISettingsService
         await SaveAsync(settings);
     }
 
+    public async Task<int> GetSetupStepAsync() => (await LoadAsync()).SetupStep;
+    public async Task SetSetupStepAsync(int step)
+    {
+        var settings = await LoadAsync();
+        settings.SetupStep = Math.Clamp(step, 0, 4);
+        await SaveAsync(settings);
+    }
+
     private async Task<AppSettings> LoadAsync()
     {
         if (!File.Exists(SettingsPath))
@@ -52,5 +60,6 @@ public class SettingsService : ISettingsService
     private class AppSettings
     {
         public string? ClubName { get; set; }
+        public int SetupStep { get; set; }
     }
 }