refactor(reader): serve pages as static files instead of base64

Replace the per-page API call (base64 payload) with static image URLs
served directly by Caddy from public/images/pages/{chapterId}/.

- LocalImageStorage now stores to public/images/ (was MANGA_DATA_PATH)
- LegacyChapterRepository returns /images/pages/{id}/{file} URLs,
  uses getimagesize() instead of loading file content into memory
- Delete GetChapterPage query/handler/response, ChapterPageResource,
  ChapterPageProvider, PageContent model
- Remove getPageContent() from ChapterRepositoryInterface
- Frontend: loadChapter() fetches chapter + all pages in parallel,
  ReaderPage uses URL instead of base64 data URI, InfiniteReader drops
  lazy-load observer side effect, readerStore drops loadedPages/preload
- GetChapterPagesTest: extract fixture images from CBZ at runtime,
  ignore tests/Fixtures/pages/ in .gitignore

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

config/services.yaml

@@ -131,7 +131,7 @@ services:
 
     App\Domain\Scraping\Infrastructure\Service\LocalImageStorage:
         arguments:
-            $storagePath: '%env(MANGA_DATA_PATH)%'
+            $storagePath: '%kernel.project_dir%/public/images'
             
     # Shared Manga Path/File Manager
     App\Domain\Shared\Domain\Contract\MangaPathManagerInterface: