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/CMakeLists.txt

@@ -56,7 +56,8 @@ target_include_directories(mtproto PUBLIC src/proto)
 target_link_libraries(mtproto PUBLIC mt3p::sodium mt3p::minilzo)
 target_compile_features(mtproto PUBLIC cxx_std_20)
 
-# --- port_logic: 40250 logic mirror (extension/src/port, docs/PORT-PLAN.md) ---
+# --- port_logic + port_platform: 40250 mirror (extension/src/port) and its platform layer
+#     (extension/src/platform), docs/PORT-PLAN.md ---
 add_subdirectory(src/port)
 
 # Host-only CLIs + tests: they run on the build machine, so skip them entirely
@@ -189,7 +190,7 @@ add_library(mtgodot ${MT_LIB_KIND}
     src/proto/proto_node.cpp
 )
 target_compile_features(mtgodot PRIVATE cxx_std_20)
-target_link_libraries(mtgodot PRIVATE godot::cpp xrender::libgr2 xrender::formats mtnet mtproto port_logic)
+target_link_libraries(mtgodot PRIVATE godot::cpp xrender::libgr2 xrender::formats mtnet mtproto port_platform)
 
 # Godot's .gdextension expects, per platform:
 #   project/bin/libmtgodot.macos.template_{debug,release}.dylib