fix(updates): persist background check timestamp (#242)

Author: mchave3

src/Foundry/Services/Settings/JsonAppSettingsService.cs

@@ -19,6 +19,7 @@ namespace Foundry.Services.Settings;
 internal sealed partial class JsonAppSettingsService : IAppSettingsService
 {
     private readonly ILogger logger;
+    private readonly object saveLock = new();
 
     /// <summary>
     /// Initializes a new instance of the <see cref="JsonAppSettingsService"/> class.
@@ -46,16 +47,19 @@ public JsonAppSettingsService(ILogger logger)
     /// <inheritdoc />
     public void Save()
     {
-        try
+        lock (saveLock)
         {
-            Directory.CreateDirectory(Constants.SettingsDirectoryPath);
-            string json = JsonSerializer.Serialize(Current, FoundryAppSettingsJsonContext.Default.FoundryAppSettings);
-            File.WriteAllText(Constants.AppSettingsPath, json);
-        }
-        catch (Exception ex)
-        {
-            logger.Error(ex, "Failed to save app settings. SettingsPath={SettingsPath}", Constants.AppSettingsPath);
-            throw;
+            try
+            {
+                Directory.CreateDirectory(Constants.SettingsDirectoryPath);
+                string json = JsonSerializer.Serialize(Current, FoundryAppSettingsJsonContext.Default.FoundryAppSettings);
+                File.WriteAllText(Constants.AppSettingsPath, json);
+            }
+            catch (Exception ex)
+            {
+                logger.Error(ex, "Failed to save app settings. SettingsPath={SettingsPath}", Constants.AppSettingsPath);
+                throw;
+            }
         }
     }
 

src/Foundry/Services/Updates/ApplicationUpdateService.cs

@@ -316,6 +316,9 @@ private void ClearPendingUpdate()
 
     private ApplicationUpdateCheckResult PublishCheckResult(ApplicationUpdateCheckResult result)
     {
+        appSettingsService.Current.Updates.LastCheckedAt = DateTimeOffset.Now;
+        appSettingsService.Save();
+
         updateStateService.Publish(result);
         return result;
     }

src/Foundry/ViewModels/Settings/AppUpdateSettingViewModel.cs

@@ -131,11 +131,6 @@ private async Task CheckForUpdateAsync()
             try
             {
                 ApplicationUpdateCheckResult result = await applicationUpdateService.CheckForUpdatesAsync();
-                DateTimeOffset checkedAt = DateTimeOffset.Now;
-                appSettingsService.Current.Updates.LastCheckedAt = checkedAt;
-                appSettingsService.Save();
-
-                LastUpdateCheck = FormatLastUpdateCheck(checkedAt);
                 ApplyCurrentUpdateState(result);
             }
             finally
@@ -242,6 +237,7 @@ private void OnLanguageChanged(object? sender, ApplicationLanguageChangedEventAr
         private void ApplyCurrentUpdateState(ApplicationUpdateCheckResult? result)
         {
             currentCheckResult = result;
+            LastUpdateCheck = FormatLastUpdateCheck(appSettingsService.Current.Updates.LastCheckedAt);
 
             if (result is null)
             {