2. Platform baseline

• Windows: Windows 10 1903+, any DX12-capable GPU including integrated (~2015+ Intel/AMD iGPU).
• macOS: macOS 13+ (ScreenCaptureKit floor), Metal via wgpu.
• Linux: Ubuntu 24.04 or newer, x86_64 (the release runner’s glibc is the floor), Vulkan via wgpu, and a PulseAudio-protocol sound server — PipeWire’s pipewire-pulse or PulseAudio itself (ADR-0131). The reference machine runs Arch on the PipeWire stack (ADR-0241), which sits above this floor on purpose. The floor is the release runner’s glibc, because a binary linked against a rolling distribution’s glibc runs on nothing older, so the tarball is built on ubuntu-latest and never on the reference box.
• foobar2000: current stable release, Windows only (per ADR-0001).
• Scene code never branches on backend or OS; the baseline constrains shader features globally.