feat(ui): Hub Navigation, Profile Dashboard and Auth Stability Fixes (#31)

This PR implements the Hub Navigation system and the Profile Dashboard, while resolving critical session synchronization issues.

### Key Changes
- **Hub Navigation**: Introduced `MainHubLayout` with a premium glassmorphism sidebar, providing access to Dashboard, Library, Concepts Map, and Profile.
- **Profile Dashboard**: Implemented a high-fidelity Profile page (#27) with learning metrics, AI token usage tracking, and system rank visualization.
- **Stability Fixes**:
    - Resolved an infinite network loop on the `/profile` page by implementing request deduplication and in-memory caching in `IdentityService`.
    - Added environment-aware guards to prevent illegal JavaScript interop calls during server-side prerendering.
    - Implemented automatic session invalidation on `401 Unauthorized` responses to handle stale authentication states gracefully.
- **Reader Integration**: Added a "Return to Dashboard" option in the reader toolbar (#26).

Closes #26
Closes #27

Reviewed-on: #31
Co-authored-by: Marek Jasiński <jasins.marek@gmail.com>
Co-committed-by: Marek Jasiński <jasins.marek@gmail.com>

src/NexusReader.Application/Commands/Sync/UpdateReadingProgressCommand.cs

@@ -3,4 +3,11 @@ using MediatR;
 
 namespace NexusReader.Application.Commands.Sync;
 
-public record UpdateReadingProgressCommand(string PageId, string UserId, string? ExcludedConnectionId = null) : IRequest<Result>;
+public record UpdateReadingProgressCommand(
+    string PageId, 
+    string UserId, 
+    Guid EbookId, 
+    double Progress, 
+    string? ChapterTitle,
+    int ChapterIndex,
+    string? ExcludedConnectionId = null) : IRequest<Result>;