Add dashboard time format setting with 12/24-hour override

src/Aspire.Dashboard/Components/Dialogs/SettingsDialog.razor

@@ -32,6 +32,17 @@
             <p class="setting-subtext">@Loc[nameof(Dialogs.SettingsDialogLanguagePageReloads)]</p>
         </div>
 
+        <div class="input-container">
+            <FluentSelect
+                TOption="TimeFormat"
+                Label="@Loc[nameof(Dialogs.SettingsDialogTimeFormat)]"
+                Items="@(Enum.GetValues<TimeFormat>())"
+                OptionText="@(i => FormatTimeFormatOption(i))"
+                @bind-SelectedOption="@_timeFormat"
+                @bind-SelectedOption:after="OnTimeFormatChanged"
+                Position="SelectPosition.Below" />
+        </div>
+
         <div>
             <span class="setting-title">@Loc[nameof(Dialogs.SettingsDialogDashboardLogsAndTelemetry)]</span>
             <div>

src/Aspire.Dashboard/Components/Dialogs/SettingsDialog.razor.cs

@@ -15,6 +15,7 @@ public partial class SettingsDialog : IDialogContentComponent, IDisposable
     private string? _currentSetting;
     private List<CultureInfo> _languageOptions = null!;
     private CultureInfo? _selectedUiCulture;
+    private TimeFormat _timeFormat;
 
     private IDisposable? _themeChangedSubscription;
 
@@ -30,6 +31,12 @@ public partial class SettingsDialog : IDialogContentComponent, IDisposable
     [Inject]
     public required DashboardDialogService DialogService { get; init; }
 
+    [Inject]
+    public required BrowserTimeProvider TimeProvider { get; init; }
+
+    [Inject]
+    public required ILocalStorage LocalStorage { get; init; }
+
     protected override void OnInitialized()
     {
         _languageOptions = GlobalizationHelpers.OrderedLocalizedCultures;
@@ -39,6 +46,8 @@ protected override void OnInitialized()
             // Otherwise, Blazor has fallen back to a supported language
             CultureInfo.CurrentUICulture;
 
+        _timeFormat = TimeProvider.TimeFormat;
+
         _currentSetting = ThemeManager.SelectedTheme ?? ThemeManager.ThemeSettingSystem;
 
         // Handle value being changed in a different browser window.
@@ -99,6 +108,26 @@ private async Task LaunchManageDataAsync()
         await DialogService.ShowDialogAsync<ManageDataDialog>(parameters);
     }
 
+    private async Task OnTimeFormatChanged()
+    {
+        TimeProvider.SetTimeFormat(_timeFormat);
+        await LocalStorage.SetAsync(BrowserStorageKeys.TimeFormat, _timeFormat);
+
+        // Reload the page to ensure all components pick up the new format
+        var uri = new Uri(NavigationManager.Uri)
+            .GetComponents(UriComponents.PathAndQuery, UriFormat.Unescaped);
+
+        NavigationManager.NavigateTo(uri, forceLoad: true);
+    }
+
+    private string FormatTimeFormatOption(TimeFormat format) => format switch
+    {
+        TimeFormat.System => Loc[nameof(Dashboard.Resources.Dialogs.SettingsDialogTimeFormatSystem)],
+        TimeFormat.TwelveHour => Loc[nameof(Dashboard.Resources.Dialogs.SettingsDialogTimeFormatTwelveHour)],
+        TimeFormat.TwentyFourHour => Loc[nameof(Dashboard.Resources.Dialogs.SettingsDialogTimeFormatTwentyFourHour)],
+        _ => format.ToString()
+    };
+
     public void Dispose()
     {
         _themeChangedSubscription?.Dispose();

src/Aspire.Dashboard/Components/Layout/MainLayout.razor.cs

@@ -114,6 +114,12 @@ protected override async Task OnInitializedAsync()
         TimeProvider.SetBrowserTimeZone(result.TimeZone);
         TelemetryContextProvider.SetBrowserUserAgent(result.UserAgent);
 
+        var timeFormatResult = await LocalStorage.GetAsync<TimeFormat>(BrowserStorageKeys.TimeFormat);
+        if (timeFormatResult.Success)
+        {
+            TimeProvider.SetTimeFormat(timeFormatResult.Value);
+        }
+
         await DisplayUnsecuredEndpointsMessageAsync();
 
         _aiDisplayChangedSubscription = AIContextProvider.OnDisplayChanged(() => InvokeAsync(StateHasChanged));

src/Aspire.Dashboard/Model/BrowserTimeProvider.cs

@@ -36,4 +36,18 @@ public void SetBrowserTimeZone(string? timeZone)
         _logger.LogDebug("Browser time zone set to '{TimeZone}' with UTC offset {UtcOffset}.", timeZoneInfo.Id, timeZoneInfo.BaseUtcOffset);
         _browserLocalTimeZone = timeZoneInfo;
     }
+
+    public TimeFormat TimeFormat { get; private set; } = TimeFormat.System;
+
+    public void SetTimeFormat(TimeFormat timeFormat)
+    {
+        TimeFormat = timeFormat;
+    }
+}
+
+public enum TimeFormat
+{
+    System,
+    TwelveHour,
+    TwentyFourHour
 }

src/Aspire.Dashboard/Resources/Dialogs.resx

@@ -549,4 +549,16 @@
   <data name="ManageDataResource" xml:space="preserve">
     <value>Resource</value>
   </data>
-</root>
+  <data name="SettingsDialogTimeFormat" xml:space="preserve">
+    <value>Time Format</value>
+  </data>
+  <data name="SettingsDialogTimeFormatSystem" xml:space="preserve">
+    <value>System</value>
+  </data>
+  <data name="SettingsDialogTimeFormatTwelveHour" xml:space="preserve">
+    <value>12-Hour</value>
+  </data>
+  <data name="SettingsDialogTimeFormatTwentyFourHour" xml:space="preserve">
+    <value>24-Hour</value>
+  </data>
+</root>