fix(anime): HxH episode thumbnails and watched-season stability on anime detail

[Thunderhawkk]

Summary

1. HxH 2011 wrong episode thumbnails (src/lib/providers/anime-episode-build.ts): AniZip keys 59–78 carry correct Greed Island titles but Chimera-Ant-era identity (absolute 117–136, tvdbId 4798644+, wrong stills/airdates, S2E59–78). mergeAniZipEpisodes copied all of it unchecked, poisoning TVDB matching, proxy overlay, and season buckets (59–78 repeats). Now skips identity fields (thumbnail, airdate, absolute, tvdbId, rating, imdb coords) on absolute-number mismatch — gated to HxH 2011 IDs only (kitsu 6448, mal/anilist 11061, anidb 8550, thetvdb 252322, tt2098220, tmdb 46298). Text enrichment untouched; every other anime byte-identical.

2. Franchise season reset to S1 (anime-episodes.tsx, use-anime-preferred-season.ts): detail page landed on the progress season then jumped to S1/Page 1 when late data arrived. First-unwatched scan skips unelectable entries (S0 specials, standalone split siblings via the split map, natively-colliding siblings); resume lookup prefers the entry the resume belongs to; pagination resets only on explicit picks.

Why

Both bugs are upstream-data shapes the merge/selection code trusted unchecked: AniZip's corrupted HxH identity block, and merged franchise pools containing entries that can't be placed in the displayed season list (TYBW native 1:1, S0 specials) winning the preferred-season election. Fixes are placed at the election/merge points with allowlist scoping (HxH) and architecture-aware skips (split standalone entries keep their own pages), so behavior only changes where it was wrong.

Verification

• pnpm run typecheck (tsc -b --pretty false) — clean across both commits.
• Manual, HxH: S2 episode thumbnails match TMDB/TVDB, loading backdrop and detail agree, no 59–78 repeats at series end.
• Manual, Bleach: 2004 page (TMDB-opened, completed library) lands on the user's progress position on progress load and holds through franchise/TVDB/proxy arrivals — confirmed via temporary transition trace (since removed).

Platform Impact

None

Checklist

• This pull request is focused and contains no unrelated refactors.
• I ran vp check for the changed files.
• I ran vp run typecheck after TypeScript changes.
• I ran the relevant Cargo checks after Rust changes.
• I tested affected platforms when the change is platform-specific.
• I preserved playback, navigation, and configured hotkey behavior where applicable.
• I added or updated tests for behavior changes.
• I removed secrets, tokens, private URLs, and personal data from logs and screenshots.