The decoder's NV12 dmabuf imports per-plane (R8 + GR88, explicit DRM
format modifier, dedicated dup'd-fd import, FOREIGN→graphics acquire)
and a fullscreen-triangle render pass converts it into the presenter's
video image with the CICP-driven coefficients ported from video_gl.rs
(same tests, plus a rows-vs-matrix agreement check). SPIR-V is committed
(shaders/build.sh regenerates) so builds and CI need no toolchain. The
import extension set is probed at device creation; unsupported boxes and
3-failure streaks demote the decoder to software via the existing
force_software contract. The session binary now honors the Settings
decoder preference instead of forcing software.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
