Add the renderer process

The renderer becomes two programs: the adapter (t5deRenderEngine.dll, 32-bit, in IMVU's process) and a 64-bit renderer process (t5de-renderer.exe) drawing with Diligent Engine, fetched with FetchContent and pinned. For now a spike: the adapter starts the renderer process for each engine and signals each frame through a shared memory channel, and the renderer process draws a box into a child window in the client's 3D view.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

adapter/log.hpp

@@ -0,0 +1,18 @@
+#pragma once
+// The renderer's log: %TEMP%\t5de-renderer.log, replaced each time the client starts.
+
+#include <format>
+#include <string_view>
+#include <utility>
+
+namespace t5de::log {
+
+void write(std::string_view line);
+
+template <class... Args>
+void info(std::format_string<Args...> format, Args&&... args)
+{
+    write(std::format(format, std::forward<Args>(args)...));
+}
+
+} // namespace t5de::log