feat(intelligence): implement Global AI Q&A screen and paywall blocker

- Implemented standard empty and active chat conversation states for the `/intelligence` page
- Created interactive `AiResponseRenderer` with AOT-compliant sentence splitting and payment gateway simulation
- Added scoped `LibraryStateService` to synchronize book ownership and updates across the application
- Obfuscated paywalled content in DOM to prevent inspection bypass
- Fixed local port connection mismatch by updating API configurations to use port 5104

src/NexusReader.UI.Shared/Pages/Catalog.razor

@@ -1,5 +1,6 @@
 @page "/catalog"
 @attribute [Authorize]
+@implements IDisposable
 @using NexusReader.UI.Shared.Components.Organisms
 @using NexusReader.Application.DTOs.User
 @using NexusReader.UI.Shared.Services
@@ -7,6 +8,7 @@
 @inject HttpClient Http
 @inject IReaderNavigationService ReaderNavigation
 @inject NavigationManager NavigationManager
+@inject ILibraryStateService LibraryStateService
 
 <div class="catalog-page">
     <header class="catalog-header">
@@ -189,6 +191,11 @@
     private bool _isLoading = true;
     private List<LastReadBookDto>? _books;
 
+    protected override void OnInitialized()
+    {
+        LibraryStateService.OnBooksChanged += HandleBooksChanged;
+    }
+
     protected override async Task OnAfterRenderAsync(bool firstRender)
     {
         if (firstRender)
@@ -197,6 +204,11 @@
         }
     }
 
+    private void HandleBooksChanged()
+    {
+        _ = InvokeAsync(LoadBooksAsync);
+    }
+
     private async Task LoadBooksAsync()
     {
         _isLoading = true;
@@ -231,4 +243,9 @@
         // Showcase callback
         NavigationManager.NavigateTo("/profile");
     }
+
+    public void Dispose()
+    {
+        LibraryStateService.OnBooksChanged -= HandleBooksChanged;
+    }
 }