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/Organisms/ReaderFooter.razor.css

@@ -18,9 +18,11 @@
 }
 
 .navigation-controls {
-    display: flex;
+    display: grid;
+    grid-template-columns: 32px 1fr 32px;
     align-items: center;
-    gap: 1rem;
+    gap: 0.75rem;
+    width: 260px;
     flex-shrink: 0;
 }
 
@@ -51,18 +53,23 @@
 
 .chapter-info {
     display: flex;
+    flex-direction: column;
     align-items: center;
-    gap: 0.5rem;
-    font-size: 0.85rem;
+    justify-content: center;
+    min-width: 0;
+    overflow: hidden;
     color: #333;
-    white-space: nowrap;
 }
 
 .chapter-title {
     font-weight: 600;
-    max-width: 180px;
+    font-size: 0.75rem;
+    max-width: 100%;
     overflow: hidden;
     text-overflow: ellipsis;
+    white-space: nowrap;
+    text-align: center;
+    line-height: 1.2;
 }
 
 .chapter-count {