fix(di): resolve client-side WASM dependency injection validation errors on login

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

@@ -5,7 +5,7 @@
 <section class="current-reading-card glass-panel">
     @if (Book != null)
     {
-        <div class="card-layout">
+        <div @key='"current-reading-book"' class="card-layout">
             <div class="book-cover">
                 <img src="@(Book.CoverUrl ?? "https://via.placeholder.com/120x180?text=No+Cover")" alt="@Book.Title" />
             </div>
@@ -51,7 +51,7 @@
     }
     else
     {
-        <div class="empty-state">
+        <div @key='"current-reading-empty"' class="empty-state">
             <div class="empty-icon">
                 <NexusIcon Name="book-open" Size="48" />
             </div>