Every DVD read path — the file-backed mux highway (build_iso_pipeline) and
the live-drive single-pass DiscStream — now resolves the per-VTS CSS title
key through one shared step, css::resolve_dvd_title_key, cracked keylessly in
playback order from the title's own extents. Removes the earlier design that
reused a single scan-time key (meaningless for a per-VTS scheme) and muxed a
detection-miss disc's scrambled sectors as garbage.
- Disc::scan no longer cracks a key up front; it does only the CSS bus-auth
read-unlock, hoisted before the UDF prefetch so scrambled small/menu VOBs
no longer cost a rejected read each (CSS-DVD scan ~25s -> ~6s).
- An uncrackable title hard-fails (E7023) instead of passing ciphertext as
plaintext; --raw skips the crack entirely; a Stop mid-crack surfaces Halted.
- DiscStream::new is now fallible and threads raw + halt.
- Fix a stale codec-parser doc claim (TrueHD/FLAC/MP2/AAC do gate via DropTally).
Matthew Jackson
52fd0f733a