forge_aupresets: project states as standard .aupreset files

Writes every dead device's exact state into ~/Library/Audio/Presets/
<Manu>/<Plugin>/ so any AU host's preset menu serves them - AU Lab
(x86_64-only, so always Rosetta, hosts Intel AUs in-process) becomes a
zero-install lightweight standalone for auditioning old presets.
Reaktor v5 VST2 chunks go into vstdata verbatim: verified headless that
the AU accepts and upgrades them to the modern container - Reaktor
state is fully recoverable after all.