port 2A step 4: platform skeleton + rest of the 2V3 header closure

- Mirror the remaining non-Python 2V3 closure headers (98 more, 173 total): EffectLib,
  EterGrnLib, SpeedTreeLib, SphereLib, PRTerrainLib, EterImageLib, EterBase/Poly, cipher/tea,
  EterLib Grp*/IME/Input/MSWindow/StateManager, GameLib actor/map/race headers, EterPack.
- SDK shims: granny.h, SpeedTreeRT.h, imm.h, Dimm.h (the SDK MIDL header, not mirrored),
  dinput/d3dx8 additions; D3D8 render-state enums, FVF macros and the COM resource hierarchy;
  more Win32 GDI/handle types with layout static_asserts.
- PORT edits for MSVC-permissive code (typename, friend visibility, <algorithm>, pointer→uintptr_t)
  and PRTerrainLib/StdAfx.h dropping the ScriptLib/Python include.
- port_logic links the vendored cryptopp/minilzo.
- extension/src/platform: port_platform target with 103 generated stub files (1917 function
  stubs, 146 static members) from the new platform_stub.py (clang -ast-dump-filter);
  MT_PLATFORM_STUB() marks every unimplemented body. libmtgodot links port_platform and
  port_gate.sh builds it.

Gate: macOS, Android, iOS, Windows (mingw) PASS; Linux BLOCKED (no toolchain).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

extension/src/platform/PlatformStub.h

@@ -0,0 +1,46 @@
+#pragma once
+// Support for the generated platform skeleton (platform_stub.py, docs/PORT-PLAN.md 2A). A function whose
+// body still starts with MT_PLATFORM_STUB() has no platform implementation yet; it does nothing and
+// returns a default value. With MT_PLATFORM_STUB_TRACE set in the environment, the first call of each
+// one is reported on stderr.
+
+#include <cstdlib>
+#include <type_traits>
+
+void mt_platform_stub_called(const char* function, bool* reported);
+
+#define MT_PLATFORM_STUB()                                    \
+	do                                                        \
+	{                                                         \
+		static bool mt_platform_stub_reported = false;        \
+		mt_platform_stub_called(__func__, &mt_platform_stub_reported); \
+	} while (0)
+
+template <class T>
+T mt_platform_stub_return()
+{
+	if constexpr (std::is_reference_v<T>)
+	{
+		using U = std::remove_cv_t<std::remove_reference_t<T>>;
+		if constexpr (std::is_default_constructible_v<U> && !std::is_abstract_v<U>)
+		{
+			static U value{};
+			return static_cast<T>(value);
+		}
+		else
+		{
+			// Never constructed: a caller that uses the referent of an unimplemented platform function
+			// is a bug the stub cannot hide.
+			alignas(U) static unsigned char storage[sizeof(U)];
+			return static_cast<T>(*reinterpret_cast<U*>(storage));
+		}
+	}
+	else if constexpr (std::is_default_constructible_v<T>)
+	{
+		return T{};
+	}
+	else
+	{
+		std::abort();
+	}
+}