experiment: LivingPlane repeatable + standalone UE runtime module (L164)

Readback barrier fix (GL_TEXTURE_UPDATE_BARRIER_BIT before glGetTexImage); check_repeatability.py compares full-field
checksums across query/capture settings - Intel GPU PASS (3b9d45905c7aafff), llvmpipe PASS, mismatch control fails.
New runtime module VoxelForgeLivingPlane (separate from generation): RDG global shader (Shaders/LivingPlane.usf),
ping-pong RGBA32F render targets, actor with WPO plane and object inputs, no CPU readback. Compiles in Linux UE 5.7.
Windows build: Source/VoxelForgeLivingPlane/*, Shaders/LivingPlane.usf, VoxelForge.uplugin. Setup: UE-SETUP.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Source/VoxelForgeLivingPlane/Private/VoxelForgeLivingPlaneModule.cpp

@@ -0,0 +1,25 @@
+#include "Modules/ModuleManager.h"
+
+#include "Interfaces/IPluginManager.h"
+#include "Misc/Paths.h"
+#include "ShaderCore.h"
+
+class FVoxelForgeLivingPlaneModule final : public IModuleInterface
+{
+public:
+	virtual void StartupModule() override
+	{
+		const TSharedPtr<IPlugin> Plugin = IPluginManager::Get().FindPlugin(TEXT("VoxelForge"));
+		if (!Plugin.IsValid())
+		{
+			UE_LOG(LogTemp, Error, TEXT("VoxelForgeLivingPlane could not find its owning plugin."));
+			return;
+		}
+
+		AddShaderSourceDirectoryMapping(
+			TEXT("/Plugin/VoxelForgeLivingPlane"),
+			FPaths::Combine(Plugin->GetBaseDir(), TEXT("Shaders")));
+	}
+};
+
+IMPLEMENT_MODULE(FVoxelForgeLivingPlaneModule, VoxelForgeLivingPlane)