Route titles with a dtsx/dtsy sample entry to MP4 via MP4Box, since Matroska has no CodecID for DTS-UHD. Add per-rendition HLS audio codec selection, fix merge_segments progress and its cleanup path.
A song skips the muxer, so the decrypted fragmented MP4 was the delivered file: its header states a length of zero and FLAC in an MP4 is not a FLAC stream, so playback stopped early and tagging failed.
Delete the dead grouped-download block, the planner, and the music service hooks; Song now flows through the one download loop, gets tagged via tag_file, and answers -w with {disc}x{track} keys.
BREAKING CHANGE: GROUP_AUDIO_DOWNLOADS, get_music_track_options and get_music_collection_label are gone. A music service returns one Audio track per quality and lets the framework choose.
Episode gains an additive absolute field services can set, an {absolute}
naming token (3-wide), and an --enrich fill from TVDB's absolute order
that never rewrites season or episode numbers.
Document tvdb_api_key, tvdb_pin, tvdb_order and metadata_providers, the
--tvdb and --tvdb-order flags with their behaviour when an order does
not cover a whole series, the new REST API parameters, and the Matroska
TVDB2 tag prefixes.
Detect the dot/space style from the full folder template instead of per segment, so `{artist}/{album} ({year})` no longer yields `Some.Artist/Some Album (2025)`. Also drops empty `[]` groups like the existing `()` handling and removes redundant cleanup passes.