feat(ui/arch): Optimize Graph Dynamics, Immersive Reader, and Core Stability (#19)

This PR introduces a major optimization of graph dynamics, immersive reading experience, and architectural stabilization.

### 🚀 Key Improvements

- **Knowledge Graph (Fix #16)**:
  - Implemented smooth D3.js transitions using the General Update Pattern.
  - Added "Neon Flash" entry animations and dynamic node dimming for better focus.
- **Immersive Reader (Fix #12)**:
  - Standardized centered layout (`max-width: 800px`) with **Merriweather** typography.
  - Optimized line-height and letter-spacing for premium readability.
- **Technical Code Blocks (Fix #20)**:
  - High-contrast dark containers for code snippets.
  - **JetBrains Mono** integration and neon-accented scrollbars.
- **Architectural Stabilization**:
  - Enforced a strict **'no async void'** policy in UI services using `Func<Task>`.
  - Resolved WASM runtime DI errors by implementing dummy service proxies for server-side dependencies.
  - Replaced generic 'Not Found' message with a branded Nexus preloader.

Fixes #7, Fixes #12, Fixes #16, Fixes #20.

Reviewed-on: #19
Co-authored-by: Marek Jasiński <jasins.marek@gmail.com>
Co-committed-by: Marek Jasiński <jasins.marek@gmail.com>

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

@@ -22,8 +22,8 @@
 
     protected override async Task OnInitializedAsync()
     {
-        QuizState.OnQuizRequested += HandleQuizRequested;
-        FocusMode.OnFocusModeChanged += StateHasChanged;
+        QuizState.OnQuizRequested += HandleQuizRequestedAsync;
+        FocusMode.OnFocusModeChanged += HandleUpdate;
         await FocusMode.InitializeAsync();
     }
 
@@ -54,16 +54,18 @@
         }
     }
 
-    private void HandleQuizRequested(string blockId)
+    private async Task HandleQuizRequestedAsync(string blockId)
     {
         _activeQuizBlockId = blockId;
-        StateHasChanged();
+        await InvokeAsync(StateHasChanged);
     }
 
+    private Task HandleUpdate() => InvokeAsync(StateHasChanged);
+
     public async ValueTask DisposeAsync()
     {
-        QuizState.OnQuizRequested -= HandleQuizRequested;
-        FocusMode.OnFocusModeChanged -= StateHasChanged;
+        QuizState.OnQuizRequested -= HandleQuizRequestedAsync;
+        FocusMode.OnFocusModeChanged -= HandleUpdate;
         
         if (_interopModule != null && _keydownHandler != null)
         {