feat(library): search a book on Goodreads from the library and reader (#4543) (#4548)

Adds a quick "Search on Goodreads" action so readers can jump straight to
Goodreads to track a book instead of retyping the title there.

- Library: a Goodreads button in the Book Details view (works on web,
  desktop and mobile) searching the book's title + author, plus a
  "Search on Goodreads" item in the desktop right-click context menu.
- Reader: Goodreads is added as a built-in web-search provider so
  highlighted text (e.g. a short-story title inside a magazine) can be
  looked up on Goodreads. Disabled by default like the other built-ins;
  enable it in Settings -> Dictionaries.

Both surfaces are used because the native context menu is desktop-only;
the Book Details button covers web and mobile. Adds a shared
openExternalUrl() helper and translates "Search on Goodreads" across all
locales (the Goodreads brand name is kept verbatim).

Closes #4543

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/readest-app/src/components/metadata/BookDetailView.tsx

@@ -9,9 +9,12 @@ import {
   MdExpandMore,
   MdExpandLess,
 } from 'react-icons/md';
+import { FaGoodreads } from 'react-icons/fa';
 
 import { Book } from '@/types/book';
 import { BookMetadata } from '@/libs/document';
+import { openExternalUrl } from '@/utils/open';
+import { getBookGoodreadsQuery, getGoodreadsSearchUrl } from '@/utils/goodreads';
 import { useTranslation } from '@/hooks/useTranslation';
 import { useSettingsStore } from '@/store/settingsStore';
 import { useEnv } from '@/context/EnvContext';
@@ -98,6 +101,12 @@ const BookDetailView: React.FC<BookDetailViewProps> = ({
                 <MdOutlineEdit className='hover:fill-blue-500' />
               </button>
             )}
+            <button
+              onClick={() => openExternalUrl(getGoodreadsSearchUrl(getBookGoodreadsQuery(book)))}
+              title={_('Search on Goodreads')}
+            >
+              <FaGoodreads className='fill-base-content' />
+            </button>
             {onDelete && (
               <Dropdown
                 label={_('Delete Book Options')}