Add lcameraBuff Stage 2 plugin with YUV attach and unit tests.

Introduce params parsing, pixel/format decisions, capture layout, shared
YuvStimProducer per camera, and channel stimulus buffers with attach flow.

Co-authored-by: Cursor <cursoragent@cursor.com>

stimBuffApis/lcameraBuff/yuvCaptureLayout.cpp

@@ -0,0 +1,49 @@
+#include <yuvCaptureLayout.h>
+#include <stdexcept>
+
+namespace smo {
+namespace stim_buff {
+namespace lcamera_buff {
+
+YuvCaptureLayoutPath classifyYuvCaptureLayoutPath(
+	const lcamera_dev::LcameraDevConfiguredCameraMode& configuredMode)
+{
+	if (configuredMode.isFullyPlanar && configuredMode.planeCount == 3u) {
+		return YuvCaptureLayoutPath::FullPlanarDirect;
+	}
+
+	if (configuredMode.planeCount == 2u) {
+		return YuvCaptureLayoutPath::SemiPlanarDeinterleave;
+	}
+
+	if (configuredMode.planeCount == 1u) {
+		return YuvCaptureLayoutPath::PackedDeinterleave;
+	}
+
+	throw std::runtime_error(
+		"lcameraBuff: unsupported configured YUV layout: pixelFormat="
+		+ configuredMode.pixelFormatName
+		+ " planeCount=" + std::to_string(configuredMode.planeCount));
+}
+
+YuvChannelBackingPlan getChannelBackingPlanForLayoutPath(
+	YuvCaptureLayoutPath layoutPath)
+{
+	switch (layoutPath)
+	{
+	case YuvCaptureLayoutPath::FullPlanarDirect:
+		return YuvChannelBackingPlan::LCameraDirect;
+
+	case YuvCaptureLayoutPath::SemiPlanarDeinterleave:
+	case YuvCaptureLayoutPath::PackedDeinterleave:
+		return YuvChannelBackingPlan::MmapDeinterleaved;
+	}
+
+	throw std::logic_error(
+		"lcameraBuff: unhandled YuvCaptureLayoutPath in "
+		"getChannelBackingPlanForLayoutPath");
+}
+
+} // namespace lcamera_buff
+} // namespace stim_buff
+} // namespace smo