DB now source of truth for folder -> Serie resolution. Changes: - AnimeSeriesService.get_by_folder(): new async lookup by folder name - SerieScanner.__read_data_from_file(): query DB first, then provider callback, then legacy key file (temporary, removed v3.0.0) - Serie: reconstruct from DB record with episode dict - Key file: warn on use, scheduled removal v3.0.0 Add unit tests for DB hit/miss/callback/fallback edge cases Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>