Refactor: Web Consolidation and Identity Stabilization (#40)

## Overview
This PR completes the architectural consolidation of the web project and stabilizes the Identity-based authentication flow for the NexusReader application. It also refines the UI aesthetic for the Book Ingestion Modal as requested in #33.

## Key Changes
- **Project Consolidation**: Fully merged `NexusReader.Web.New` into `NexusReader.Web`. This includes updating all namespace references, VS Code launch/task configurations, and CI/CD (`Dockerfile`).
- **Identity Stabilization**:
  - Implemented `IIdentityService` on the server using `SignInManager<NexusUser>` and `UserManager<NexusUser>`.
  - Fixed registration logic to include mandatory fields (`SubscriptionPlanId`, `TenantId`).
  - Updated `Login.razor` to force a page reload on successful login, ensuring proper synchronization of authentication cookies between SignalR and the browser.
- **UI/UX Refinement**:
  - Updated `BookIngestionModal` styling to follow the **Nexus Neon** design system.
  - Added premium button styles with hover effects and glows.
  - Improved modal layout and interaction feedback (shimmer effects, spinner colors).
- **Cleanup**: Removed obsolete interfaces and constants that were superseded by newer Application layer implementations.

## Verification
- Successfully built the solution: `dotnet build NexusReader.slnx --no-restore`
- Verified project structure and file moves.
- Validated server-side authentication logic.

Fixes #33

---------

Co-authored-by: Marek Jasiński <jasins.marek@gmail.com>
Reviewed-on: #40
Co-authored-by: Antigravity <antigravity@google.com>
Co-committed-by: Antigravity <antigravity@google.com>

src/NexusReader.Web.Client/Services/WasmEpubService.cs

@@ -5,11 +5,11 @@ using NexusReader.Application.Queries.Reader;
 
 namespace NexusReader.Web.Client.Services;
 
-public class WasmEpubService : IEpubService
+public class WasmEpubReader : IEpubReader
 {
     private readonly HttpClient _httpClient;
 
-    public WasmEpubService(HttpClient httpClient)
+    public WasmEpubReader(HttpClient httpClient)
     {
         _httpClient = httpClient;
     }
@@ -35,4 +35,24 @@ public class WasmEpubService : IEpubService
             return Result.Fail(new Error($"Network or parsing error: {ex.Message}").CausedBy(ex));
         }
     }
+    // Metadata extraction moved to WasmEpubMetadataExtractor
+}
+
+public class WasmEpubMetadataExtractor : IEpubMetadataExtractor
+{
+    public async Task<Result<LocalEpubMetadata>> ExtractMetadataAsync(Stream epubStream)
+    {
+        try
+        {
+            using var bookRef = await VersOne.Epub.EpubReader.OpenBookAsync(epubStream);
+            var title = bookRef.Title ?? "Unknown Title";
+            var author = bookRef.Author ?? "Unknown Author";
+            byte[]? cover = await bookRef.ReadCoverAsync();
+            return Result.Ok(new LocalEpubMetadata(title, author, cover));
+        }
+        catch (Exception ex)
+        {
+            return Result.Fail(new Error($"Failed to extract EPUB metadata locally: {ex.Message}").CausedBy(ex));
+        }
+    }
 }