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.UI.Shared/Components/Organisms/BookIngestionModal.razor.css

@@ -242,11 +242,139 @@
     transform: translateY(0);
 }
 
+/* Verification State */
+.verification-state {
+    display: flex;
+    flex-direction: column;
+    gap: 1.5rem;
+    animation: fadeIn 0.4s ease-out;
+}
+
+.verification-layout {
+    display: grid;
+    grid-template-columns: 140px 1fr;
+    gap: 2rem;
+    align-items: start;
+}
+
+.cover-preview {
+    width: 140px;
+    height: 200px;
+    border-radius: 12px;
+    overflow: hidden;
+    background: rgba(255, 255, 255, 0.03);
+    border: 1px solid rgba(255, 255, 255, 0.1);
+    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
+    position: relative;
+}
+
+.cover-preview img {
+    width: 100%;
+    height: 100%;
+    object-fit: cover;
+}
+
+.glowing-placeholder {
+    width: 100%;
+    height: 100%;
+    display: flex;
+    flex-direction: column;
+    justify-content: center;
+    align-items: center;
+    background: linear-gradient(135deg, #1a1a1a 0%, #0a0a0a 100%);
+    position: relative;
+    overflow: hidden;
+}
+
+.glowing-placeholder::after {
+    content: '';
+    position: absolute;
+    width: 150%;
+    height: 150%;
+    background: radial-gradient(circle, var(--nexus-neon-alpha, rgba(0, 255, 153, 0.15)) 0%, transparent 70%);
+    animation: pulseGlow 4s infinite alternate;
+}
+
+.glowing-placeholder svg {
+    color: var(--nexus-neon, #00ffaa);
+    opacity: 0.5;
+    z-index: 1;
+    filter: drop-shadow(0 0 10px var(--nexus-neon-alpha-deep, rgba(0, 255, 153, 0.3)));
+}
+
+.verification-form {
+    display: flex;
+    flex-direction: column;
+    gap: 1.25rem;
+}
+
+.form-group {
+    display: flex;
+    flex-direction: column;
+    gap: 0.5rem;
+}
+
+.form-group label {
+    font-size: 0.75rem;
+    text-transform: uppercase;
+    letter-spacing: 1px;
+    color: var(--nexus-text-muted, #888);
+    font-weight: 600;
+}
+
+.form-input {
+    background: rgba(255, 255, 255, 0.03);
+    border: 1px solid rgba(255, 255, 255, 0.1);
+    border-radius: 8px;
+    padding: 0.75rem 1rem;
+    color: var(--nexus-text);
+    font-family: var(--nexus-font-sans);
+    transition: all 0.3s;
+}
+
+.form-input:focus {
+    outline: none;
+    border-color: var(--nexus-neon, #00ffaa);
+    background: rgba(255, 255, 255, 0.06);
+    box-shadow: 0 0 15px rgba(0, 255, 153, 0.1);
+}
+
 .error-message {
     margin-top: 1rem;
-    color: #ff5555;
+    color: var(--nexus-error, #ff5555);
     text-align: center;
     font-size: 0.9rem;
+    padding: 0.75rem;
+    background: var(--nexus-error-alpha, rgba(255, 85, 85, 0.1));
+    border-radius: 8px;
+    border: 1px solid var(--nexus-error-alpha-deep, rgba(255, 85, 85, 0.2));
+}
+
+@keyframes pulseGlow {
+    from { transform: scale(1); opacity: 0.5; }
+    to { transform: scale(1.2); opacity: 0.8; }
+}
+
+.btn:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+    filter: grayscale(1);
+}
+
+.btn-loading {
+    position: relative;
+    color: transparent !important;
+}
+
+.btn-loading::after {
+    content: "";
+    position: absolute;
+    width: 20px;
+    height: 20px;
+    border: 2px solid rgba(0, 0, 0, 0.1);
+    border-top-color: #000;
+    border-radius: 50%;
+    animation: spin 0.8s linear infinite;
 }
 
 @keyframes fadeIn {