Live bisect on a fresh endpoint: the mix/host format keys are
RENDER-engine properties — stamped onto a capture endpoint they broke its
shared-mode graph (IsFormatSupported reported 2ch/48k OK while Initialize
failed 0x88890008 on a once-stamped fresh endpoint; unstamped it opened
fine, S3). The capture now gets ONLY the device-format key — the knob
mmsys.cpl itself writes — declaring the stereo the pins actually accept.