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/Components/Molecules/IntelligenceToolbar.razor

@@ -42,7 +42,7 @@
 @code {
     protected override void OnInitialized()
     {
-        FocusMode.OnFocusModeChanged += StateHasChanged;
+        FocusMode.OnFocusModeChanged += HandleUpdate;
     }
 
     private async Task HandleClearCache()
@@ -56,8 +56,10 @@
         }
     }
 
+    private Task HandleUpdate() => InvokeAsync(StateHasChanged);
+
     public void Dispose()
     {
-        FocusMode.OnFocusModeChanged -= StateHasChanged;
+        FocusMode.OnFocusModeChanged -= HandleUpdate;
     }
 }