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>

src/Domain/Reader/Application/Response/ChapterPageResponse.php

@@ -1,42 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace App\Domain\Reader\Application\Response;
-
-final readonly class ChapterPageResponse
-{
-    public function __construct(
-        private string $id,
-        private int $pageNumber,
-        private string $base64Content,
-        private string $mimeType,
-        private array $dimensions
-    ) {
-    }
-
-    public function getId(): string
-    {
-        return $this->id;
-    }
-
-    public function getPageNumber(): int
-    {
-        return $this->pageNumber;
-    }
-
-    public function getBase64Content(): string
-    {
-        return $this->base64Content;
-    }
-
-    public function getMimeType(): string
-    {
-        return $this->mimeType;
-    }
-
-    public function getDimensions(): array
-    {
-        return $this->dimensions;
-    }
-}