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/IDOverlayHost.cs

@@ -0,0 +1,11 @@
+namespace decePubClient.Components.Daisy;
+
+/// <summary>
+/// Where an open overlay (a dialog, a menu, a sheet) says it is open, so that the phone's Back button closes it instead
+/// of leaving the page: Open registers how to close it and returns what ends the registration once it is closed. The
+/// app cascades one (OverlayService, from MainLayout); a component without one simply doesn't register.
+/// </summary>
+public interface IDOverlayHost
+{
+	IDisposable Open(Func<Task> close);
+}