fix: ensure user-specific ebook tracking and auto-provisioning for progress sync

src/NexusReader.UI.Shared/Components/Organisms/ReaderCanvas.razor

@@ -11,6 +11,8 @@
 @inject KnowledgeCoordinator Coordinator
 @inject IReaderInteractionService InteractionService
 @inject ISyncService SyncService
+@using Microsoft.AspNetCore.Components.Authorization
+@inject AuthenticationStateProvider AuthStateProvider
 
 <div class="reader-canvas @(ThemeService.IsLightMode ? "theme-light" : "theme-dark")">
     @if (ViewModel == null)
@@ -190,7 +192,10 @@
         ViewModel = null;
         StatusMessage = "Fetching content...";
         
-        var result = await Mediator.Send(new GetReaderPageQuery(index));
+        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
+        var userId = authState.User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier)?.Value;
+
+        var result = await Mediator.Send(new GetReaderPageQuery(index, userId));
         if (result.IsSuccess)
         {
             ViewModel = result.Value;