Back closes what is open

On a phone the Back button left the page under an open menu, sheet or dialog. An open overlay now says so (new
IDOverlayHost, cascaded by MainLayout; OverlayService keeps them newest last): DModal and DDropdown through the
cascade, so the D components stay free of app services, and the nav menu, PhoneSheet and the full-screen globe through
the service. MainLayout's location-changing handler lets Back close the newest overlay instead of leaving the page; a
link followed or the app's own navigation (signing out after its question, say) closes them all and goes on. Blazor
can't tell Back from the app's navigation, so a capture-phase popstate listener in main.js marks Back
(AppStatusService.TookBack). No history entries are pushed. Phone flow: Back closes the menu, a card's More sheet, the
composer and the full-screen globe one after another without leaving the feed, and with nothing open goes back.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

Components/PhoneSheet.razor

@@ -29,8 +29,30 @@
 	[Parameter] public RenderFragment ChildContent { get; set; }
 	[Parameter] public string Class { get; set; }
 
+	[Inject] OverlayService Overlays { get; set; }
+
+	IDisposable overlay;
+
 	protected override void OnInitialized() => IsLoading = false;
 
+	// open, the Back button closes it
+	protected override void OnParametersSet()
+	{
+		if (IsOpen && overlay is null)
+			overlay = Overlays.Open(() => InvokeAsync(Close));
+		else if (!IsOpen && overlay is not null)
+		{
+			overlay.Dispose();
+			overlay = null;
+		}
+	}
+
+	public override async ValueTask DisposeAsync()
+	{
+		overlay?.Dispose();
+		await base.DisposeAsync();
+	}
+
 	Task Close() => OnClose.InvokeAsync();
 
 	Task OnKeyDown(KeyboardEventArgs e) => e.Key == "Escape" ? Close() : Task.CompletedTask;