- Add IOpenXRSwapchain::GetEyeSwapchainHandle() and SubmitStereoFlatFrame(),
with per-backend overrides for Vulkan, D3D11, D3D12, and OGL.
- Add OpenXRManager::SubmitStereoQuadFrame() which builds two world-locked
XrCompositionLayerQuad layers with XR_EYE_VISIBILITY_LEFT/RIGHT and publishes
them through the pacing thread (or EndFrame on the legacy path).
- Extend PublishedXRFrame and FrameThreadLoop to submit the stereo quad pair.
- Add UI checkbox for Stereo Screen in VRPane and VRConfigWidget.
The game renders with classic SBS stereoscopy; left/right XFB layers are blit
into the corresponding OpenXR eye swapchains and shown as a 3D floating screen.
Jeremy Bowers