Refactor stereo frame worker and interpolation tests for enhanced VR performance

- Updated stereo_frame_worker_smoke.cpp to allow dynamic headset rates and prediction lead time.
- Improved logging to include motion diagnostics and adjusted frame submission logic based on headset frequency.
- Enhanced stereo_interpolation_test.cpp with additional tests for camera motion separation and playback cadence.
- Introduced MkwVRReadSceneView function to read the camera view matrix for improved scene rendering.
- Modified VR first-person logic to support scene view reading and validation.
- Added scene_camera.hpp to encapsulate camera motion handling and inverse view calculations.
- Ensured that the VR integration layer correctly logs motion diagnostics and handles scene playback accurately.

runtime/include/vr/mkw_vr_first_person.h

@@ -573,6 +573,10 @@ void MkwVRFirstPersonRecenter() noexcept;
 // anchor has been missing long enough to give up holding the last one.
 FirstPersonAnchor MkwVRFirstPersonGetAnchor() noexcept;
 
+// Checked guest-thread read of the camera that authored this frame's GX draws.
+// Also available with first person off; render workers receive only its copy.
+bool MkwVRReadSceneView(Mtx34& view) noexcept;
+
 // Guest-frame inventory snapshot, sampled at the race draw boundary. A
 // generation change invalidates any item retained by a prior race.
 HeldItem MkwVRFirstPersonGetHeldItem() noexcept;