docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/V/VATSEvents.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "RE/V/VATS.h"
+
+namespace RE
+{
+	namespace VATSEvents
+	{
+		class ModeChange
+		{
+		public:
+			// members
+			VATS::VATS_MODE_ENUM oldMode;  // 00
+			VATS::VATS_MODE_ENUM newMode;  // 04
+		};
+		static_assert(sizeof(ModeChange) == 0x8);
+	}
+}