Add multi-source ebook support and per-indexer categories

Introduces granular toggles for Anna's Archive and Indexer Search as ebook sources, updates settings UI to a three-section layout, and documents the new configuration. Adds per-indexer category configuration with separate tabs for audiobooks and ebooks, updates API routes and types for new settings, and ensures legacy config migration. Indexer grouping and file organization logic now support the new category structure and ebook source toggles.

src/components/admin/indexers/CategoryTreeView.tsx

@@ -16,12 +16,15 @@ import {
 interface CategoryTreeViewProps {
   selectedCategories: number[];
   onChange: (categories: number[]) => void;
+  defaultCategories?: number[]; // Categories to show "Default" badge for (e.g., [3030] for audiobook, [7020] for ebook)
 }
 
 export function CategoryTreeView({
   selectedCategories,
   onChange,
+  defaultCategories = [3030], // Default to audiobook category for backwards compatibility
 }: CategoryTreeViewProps) {
+  const isDefaultCategory = (categoryId: number) => defaultCategories.includes(categoryId);
   const handleParentToggle = (parentId: number) => {
     const childIds = getChildIds(parentId);
     const allChildrenSelected = areAllChildrenSelected(parentId, selectedCategories);
@@ -75,7 +78,7 @@ export function CategoryTreeView({
               <span className="text-xs font-mono text-gray-400 dark:text-gray-500">
                 [{category.id}]
               </span>
-              {category.id === 3030 && (
+              {isDefaultCategory(category.id) && (
                 <span className="text-xs px-2 py-0.5 bg-blue-100 dark:bg-blue-900/30 text-blue-700 dark:text-blue-300 rounded-full">
                   Default
                 </span>
@@ -109,7 +112,7 @@ export function CategoryTreeView({
                     <span className="text-xs font-mono text-gray-400 dark:text-gray-500">
                       [{child.id}]
                     </span>
-                    {child.id === 3030 && (
+                    {isDefaultCategory(child.id) && (
                       <span className="text-xs px-2 py-0.5 bg-blue-100 dark:bg-blue-900/30 text-blue-700 dark:text-blue-300 rounded-full">
                         Default
                       </span>