javlibrary provider — deep-catalog fallback on /movie and /query

0.5.0

• javlibrary on /movie. New browser-scraped provider for code lookups: title, cast, genres, runtime, release date, studio, cover, sample images, and the JavLibrary page URL. No magnets or streams. See the JavLibrary API post.
• javlibrary on /query. Keyword search over codes and labels. Honors num and page; no filters and no sort beyond relevance. Any filter or non-relevance sort excludes it (or 422 if pinned). Walkthrough: how to use javlibrary.
• Waterfall ends with javlibrary. Default order is now FANZA → DMM → missav → javdb → javdatabase → javlibrary. Slowest source, deepest catalog fallback — only answers when faster providers miss or can’t satisfy the request.
• Cover enrichment on search. Query hits backfill full-res covers and release dates from the DMM/FANZA index when the code matches.