Changes:
- Add season-keyword regex (staffel, season, saison, temporada) and
episode-keyword regex (folge, episode, ep.) to reliably extract
the correct number regardless of name format
- parseChapterNumber() now encodes season context into the sort key
(season * 100000 + episode) so multi-season anime sort correctly
across seasons without mixing episode numbers
- Add parseEpisodeNumber() which strips season context and returns
only the episode number within a season; use this for tracker
updates (MAL/AniList/Kitsu) and AniSkip lookups, where the tracker
entry is already season-specific
- Switch updateTrackChapterRead and getAniSkipResults to
parseEpisodeNumber to fix incorrect episode reporting for
multi-season anime
- Compile all RegExp objects as static finals instead of per-call
instantiation
- Refactor duplicated parse logic into a single private _parse()
method with an applySeason flag
