Render all click help through rich-click, themed by a new `theme` config key (9 palettes + aliases, previewable via `unshackle env theme`), and show service docstrings in local and remote `dl <TAG> -h`.
--anilist supersedes --animeapi (REST: anilist_id); the keyless AniList
GraphQL provider joins the registry with title search, mal: ID lookup,
an ANILIST mkv tag, and the anilist_title_language config option.
Services mark anime via Service.ANIME / Title.anime for anilist-first
metadata resolution with fall-through.
Supplied IDs resolve directly via a shared resolve_by_ids and never fall back to title search; metadata_providers gains per-kind ordering and a disable_metadata switch stops all automatic lookups while explicit IDs keep working.
BREAKING: --tmdb/--imdb/--tvdb are now mutually exclusive and require a usable provider; --enrich also overwrites original language; the imdbapi provider and imdb_api_enabled are replaced by a keyless imdb provider.
--enrich now sets Title.language when the service left it unset, so video tracks stop falling back to und. Adds original_language to MetadataResult (TMDB, TVDB, OMDb, IMDxAPI) and falls back to OMDb for --imdb, which previously did nothing while imdb_api_enabled defaults to false.