v0.47.0 - generated music, share links, audio export, retro-audio engines in the off-main-thread host

Generated game music (mwg/music), bar-quantised adaptive music, share links in the URL fragment, an audio export service (WAV, FLAC and Opus) with bus recording, the mwg-audio audit, bench, share and convert tools, and an off-main-thread audio host that runs the retro-audio package's own engines from a bundled script. Against the package's engines the host's output is identical to a direct render for all 48 catalogue engines, and the D-50 at 16 voices, which the main thread cannot keep up with, plays on the worker without an underrun. Also DX7 voice metadata and a patch inspector hook for verifyPackage, and the project's sponsorship metadata. Nothing here is breaking.

See CHANGELOG.md for the full list.