feat(frontend): add delete confirmation modal for library management

-- Add dedicated delete confirmation modal to admin/library page
-- Refactor deleteLibrary() to use modal instead of inline confirm()
-- Add showDeleteModal(), hideDeleteModal(), confirmDeleteLibrary() functions
-- Modal displays clear warning about what gets deleted
-- Improves UX by making the confirmation dialog more prominent and informative

web/src/library.ts

@@ -195,33 +195,7 @@ async function deleteLibrary(libraryId: string): Promise<void> {
     const library = libraries.find(l => l.id === libraryId);
     if (!library) return;
 
-    const message = `Are you sure you want to delete "${library.name}"?
-
-This will remove:
-• Library metadata from the database
-• All folder references
-• All book records from the database
-
-⚠️ Book files on disk will NOT be deleted.
-
-This action cannot be undone.`;
-
-    if (!confirm(message)) {
-        return;
-    }
-
-    try {
-        const response = await (window as any).api.delete(`/libraries/${libraryId}`);
-        await (window as any).api.handleVoidResponse(response);
-
-        if ((window as any).showToast?.success) {
-            (window as any).showToast.success('Library deleted successfully');
-        }
-
-        await reloadLibraries();
-    } catch (error) {
-        (window as any).api.handleError(error, 'Failed to delete library');
-    }
+    showDeleteModal(library);
 }
 
 // Show library folders
@@ -361,6 +335,60 @@ function hideCreateLibraryModal(): void {
     }
 }
 
+// Delete modal state
+let libraryToDelete: Library | null = null;
+
+function showDeleteModal(library: Library): void {
+    libraryToDelete = library;
+
+    const modal = document.getElementById('delete-library-modal') as HTMLElement;
+    const content = document.getElementById('delete-modal-content') as HTMLElement;
+
+    if (modal && content) {
+        const message = `Are you sure you want to delete "<strong>${escapeHtmlLocal(library.name)}</strong>"?
+
+This will remove:
+• Library metadata from the database
+• All folder references
+• All book records from the database
+
+⚠️ Book files on disk will NOT be deleted.
+
+This action cannot be undone.`;
+
+        content.innerHTML = message.replace(/\n/g, '<br>');
+        modal.classList.remove('hidden');
+    }
+}
+
+function hideDeleteModal(): void {
+    const modal = document.getElementById('delete-library-modal') as HTMLElement;
+    if (modal) {
+        modal.classList.add('hidden');
+    }
+    libraryToDelete = null;
+}
+
+async function confirmDeleteLibrary(): Promise<void> {
+    if (!libraryToDelete) return;
+
+    const libraryId = libraryToDelete.id;
+    hideDeleteModal();
+
+    try {
+        const response = await (window as any).api.delete(`/libraries/${libraryId}`);
+        await (window as any).api.handleVoidResponse(response);
+
+        if ((window as any).showToast?.success) {
+            (window as any).showToast.success('Library deleted successfully');
+        }
+
+        await reloadLibraries();
+    } catch (error) {
+        (window as any).api.handleError(error, 'Failed to delete library');
+    }
+}
+
 // Local escape HTML helper
 function escapeHtmlLocal(text: string): string {
     const div = document.createElement('div');
@@ -443,6 +471,12 @@ function handleGlobalClick(event: Event): void {
         case 'hide-create-modal':
             hideCreateLibraryModal();
             break;
+        case 'hide-delete-modal':
+            hideDeleteModal();
+            break;
+        case 'confirm-delete':
+            void confirmDeleteLibrary();
+            break;
     }
 }
 
@@ -564,12 +598,8 @@ function initializeLibraryAdmin(): void {
         createLibraryForm.addEventListener('submit', handleCreateLibrarySubmit);
     }
 
-    // Initial data is already SSR'd, no need to fetch
-    // Just store it for updates
-    const ssrLibraries = document.querySelectorAll('#libraries-list [data-library-id]');
-    if (ssrLibraries.length === 0) {
-        // No libraries SSR'd, which is fine
-    }
+    // Load libraries from API on page load
+    void reloadLibraries();
 }
 
 // Export functions for global access
@@ -585,6 +615,9 @@ function initializeLibraryAdmin(): void {
 (window as any).navigateFolderBrowser = navigateFolderBrowser;
 (window as any).selectBrowseFolder = selectBrowseFolder;
 (window as any).hideFolderBrowser = hideFolderBrowser;
+(window as any).showDeleteModal = showDeleteModal;
+(window as any).hideDeleteModal = hideDeleteModal;
+(window as any).confirmDeleteLibrary = confirmDeleteLibrary;
 
 // Initialize on DOM ready
 if (document.readyState === 'loading') {