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.Application/Commands/Library/IngestEbookCommand.cs

@@ -0,0 +1,21 @@
+using NexusReader.Application.Abstractions.Messaging;
+
+namespace NexusReader.Application.Commands.Library;
+
+/// <summary>
+/// Command to ingest a new ebook into the library.
+/// </summary>
+/// <param name="Title">The title of the book.</param>
+/// <param name="AuthorName">The name of the author.</param>
+/// <param name="CoverImage">The raw bytes of the cover image (optional).</param>
+/// <param name="EpubData">The raw bytes of the EPUB file.</param>
+/// <param name="UserId">The ID of the user owning the book.</param>
+/// <param name="TenantId">The tenant ID for multi-tenant isolation. Defaults to "global" for single-tenant or default usage.</param>
+public record IngestEbookCommand(
+    string Title,
+    string AuthorName,
+    byte[]? CoverImage,
+    byte[] EpubData,
+    string UserId,
+    string TenantId = "global"
+) : ICommand<Guid>;