Rate-limited AniList client for discovery seeds (BL-0051)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

test/fixtures/anilist/novel.json

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+{"data":{"Media":{"id":777,"format":"NOVEL","isAdult":false,
+  "title":{"romaji":"Hon no Tabi","english":null,"native":null},
+  "synonyms":[],"status":"FINISHED","startDate":{"year":2010},
+  "averageScore":70,"popularity":1200,"trending":1,"genres":[],"tags":[],
+  "staff":{"edges":[]},"coverImage":{"extraLarge":null},"siteUrl":"https://anilist.co/manga/777"}}}