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/Daisy/Actions/DModal.razor

@@ -1,4 +1,5 @@
 @inherits DComponentBase
+@implements IDisposable
 
 @* daisyUI Modal: https://daisyui.com/components/modal/ . Always rendered; the open state lives in C# (@bind-IsOpen)
    and shows as modal-open. On opening, the box takes the focus (Blazor's FocusAsync) so that Escape, handled on the
@@ -58,7 +59,11 @@
 	[Parameter] public bool ShowClose { get; set; } = true;
 	[Parameter] public string BoxClass { get; set; }
 
+	/// <summary>Where it says it is open, so the Back button closes it (cascaded by the app; none, none said).</summary>
+	[CascadingParameter] IDOverlayHost Overlays { get; set; }
+
 	readonly string uid = "d" + Guid.NewGuid().ToString("N")[..8];
+	IDisposable overlay;
 	ElementReference box;
 	bool wasOpen;
 	bool focusPending;
@@ -80,8 +85,26 @@
 		if (IsOpen && !wasOpen)
 			focusPending = true;
 		wasOpen = IsOpen;
+		TrackOverlay();
 	}
 
+	void TrackOverlay()
+	{
+		if (IsOpen && overlay is null)
+			overlay = Overlays?.Open(() => InvokeAsync(async () =>
+			{
+				await SetOpen(false);
+				StateHasChanged();
+			}));
+		else if (!IsOpen && overlay is not null)
+		{
+			overlay.Dispose();
+			overlay = null;
+		}
+	}
+
+	public void Dispose() => overlay?.Dispose();
+
 	protected override async Task OnAfterRenderAsync(bool firstRender)
 	{
 		if (!focusPending)
@@ -98,6 +121,7 @@
 	{
 		IsOpen = isOpen;
 		wasOpen = isOpen;
+		TrackOverlay();
 		await IsOpenChanged.InvokeAsync(isOpen);
 	}
 }