Faust loader: platform-aware library lookup and AQUASYNTH_FAUST_LIBRARY override
Diff review: exactly three files: src/AquaSynth.Faust/NativeFaustRuntime.cs, tests/AquaSynth.Dsl.Tests/FaustLoaderPlatformTests.cs, and the docs file docs/faust-toolchain-boundary.md.
Faust loader: platform-aware library lookup and AQUASYNTH_FAUST_LIBRARY override