feat(ingestion): implement hybrid metadata verification form #34 (#41)

### Description
This PR implements **Issue #34: [UI/UX] Implement Hybrid Metadata Verification Form in Ingestion Modal**.

### Key Changes
- **Metadata Verification State**: Introduced a new state in `BookIngestionModal.razor` allowing users to edit `Title` and `Author` before final ingestion.
- **Cover Image Preview**: Added a high-fidelity cover preview with a CSS-based glowing placeholder fallback for books without embedded covers.
- **Ingestion Pipeline**:
  - Implemented `IngestEbookCommand` and `IngestEbookCommandHandler`.
  - Added `IBookStorageService` and its implementation for managing EPUB and cover file storage.
  - Exposed `POST /api/library/ingest` Minimal API endpoint with `.DisableAntiforgery()` to handle client-side JSON uploads.
- **Stability Fixes**:
  - Resolved DI validation errors in the WASM client by providing a dummy `IBookStorageService` registration.
  - Adjusted Kestrel request limits to handle large EPUB payloads (up to 100MB).
  - Corrected middleware ordering to ensure Antiforgery works correctly with Authentication.

### Verification
- Solution builds successfully.
- Manual verification of modal state transitions and API ingestion logic.

Closes #34.

---------

Co-authored-by: Marek Jasiński <jasins.marek@gmail.com>
Reviewed-on: #41
Reviewed-by: Marek Jaisński <jasins.marek@gmail.com>
Co-authored-by: Antigravity <antigravity@google.com>
Co-committed-by: Antigravity <antigravity@google.com>

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

@@ -48,7 +48,7 @@ public class WasmEpubMetadataExtractor : IEpubMetadataExtractor
             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));
+            return Result.Ok(new LocalEpubMetadata { Title = title, Author = author, CoverImage = cover });
         }
         catch (Exception ex)
         {