Model preview: AVA2 render-target window on a Vulkan colour target

Port of AVA2's CRenderTarget / GrpRenderTargetTexture / renderTarget module.
The host gains an RGBA8 offscreen colour pass for D3D colour render targets;
mt_preview shows wearable items on every allowed race and monsters with
motions, reached by X+click in the inventory and shop and from the wiki.
Player races are created as TYPE_PC so their parts exist.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/port/UserInterface/CRenderTargetManager.cpp

@@ -0,0 +1,74 @@
+#include "StdAfx.h"
+#include "CRenderTargetManager.h"
+#include "../EterBase/Stl.h"
+#include <memory>
+
+CRenderTargetManager::CRenderTargetManager(){}
+CRenderTargetManager::~CRenderTargetManager()
+{
+	Destroy();
+}
+void CRenderTargetManager::Destroy()
+{
+	m_renderTargets.clear();
+}
+void CRenderTargetManager::DeformModels()
+{
+	for (const auto& elem : m_renderTargets)
+		elem.second->DeformModel();
+}
+void CRenderTargetManager::UpdateModels()
+{
+	for (auto& elem : m_renderTargets)
+		elem.second->UpdateModel();
+}
+// PORT: the background is drawn into the target by RenderModel (CRenderTarget::RenderBackground).
+void CRenderTargetManager::RenderBackgrounds()
+{
+}
+void CRenderTargetManager::RenderModels()
+{
+	for (const auto& elem : m_renderTargets)
+		elem.second->RenderModel();
+}
+void CRenderTargetManager::CreateRenderTargetTextures()
+{
+	for (const auto& elem : m_renderTargets)
+		elem.second->CreateTextures();
+}
+void CRenderTargetManager::ReleaseRenderTargetTextures()
+{
+	for (const auto& elem : m_renderTargets)
+		elem.second->ReleaseTextures();
+}
+bool CRenderTargetManager::CreateRenderTarget(const int index, const int width, const int height)
+{
+	// PORT: the size check guards the recording device, which allocates the target's bytes up front.
+	if (index < 1 || GetRenderTarget(index) || width < 1 || height < 1 || width > 2048 || height > 2048)
+		return false;
+	try
+	{
+		m_renderTargets.emplace(index, std::make_shared<CRenderTarget>(width, height));
+	}
+	catch (const std::exception&)
+	{
+		return false;
+	}
+	return true;
+}
+void CRenderTargetManager::RemoveRenderTarget(const int index)
+{
+	const auto it = m_renderTargets.find(index);
+	if (it != m_renderTargets.end())
+	{
+		it->second->ResetModel();
+		m_renderTargets.erase(index);
+	}
+}
+std::shared_ptr<CRenderTarget> CRenderTargetManager::GetRenderTarget(const int index)
+{
+	const auto it = m_renderTargets.find(index);
+	if (it != m_renderTargets.end())
+		return it->second;
+	return nullptr;
+}