Parallel conversion is now the default. Running decant from the terminal now behaves the same way the Finder Quick Action already did: files convert concurrently instead of one at a time. On an 18-core M5 Max, 50 files went from 24.0s to 4.5s. --jobs 1 still forces serial conversion if you need it (e.g. for deterministic logs or a slow external disk).
Fixed
Some containers (Matroska in particular) store certain tags at the stream level rather than the container level. Decant's enrichment step correctly detected these tags as present, but they were silently dropped when building the converted output instead of being carried over. They're now mapped through correctly.
Homebrew install now matches the Quick Action decant actually ships
0.3.0 replaced the old Shortcuts-based Quick Action with a proper Automator .workflow, specifically to get rid of the per-folder permission prompt that Shortcuts forced on every album. This release fixes the Homebrew tap so brew install jzstern/tap/decant — the recommended install path — actually installs that working Automator Quick Action too, instead of leaving you with a stale, Shortcuts-based one (or none at all).