2V0-g: port the .fnt font pipeline over a FreeType GDI emulation

CGraphicText, CGraphicFontTexture and CGraphicDib are the 40250 bodies
verbatim; CGraphicTextInstance is verbatim except that its D3D draws become
UI render commands (one image quad per glyph, Bar for cursor/underline).

- platform/Win32Gdi.cpp: the GDI subset those files call, over vendored
  FreeType 2.13.3, following GDI's LOGFONT cell height, win metrics and gasp
  rules; system font lookup with substitute and CJK fallback faces
- Win32Crt: MultiByteToWideChar / WideCharToMultiByte (UTF-8 and 1252 by
  hand, other code pages through iconv)
- CGraphicImageTexture memory textures: glyph pages reach Godot as
  "mem:<id>@<revision>"; Metin2PythonHost.memory_texture + Canvas cache
- Util.cpp code page / font face table, SetDefaultCodePage at boot,
  DefaultFont_* block, fnt resource type, GetMaxTextureWidth/Height
- TextTag, StringCodec, Arabic, Vietnamese copied from 40250
- tests: port.text (Tahoma 12 metrics, alignment, CP949), port.app_loop
  and python_host_test.gd now check glyph quads instead of text commands

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

extension/src/platform/EterLib/UIRenderCommands.h

@@ -30,8 +30,22 @@ std::uint32_t UIRenderColor(const Color& color) {
 }
 
 class CGraphicTexture;
+// A file-backed texture is named by its pack path; a memory texture (CGraphicImageTexture::Create,
+// filled through Lock/Unlock: the CGraphicFontTexture glyph pages) by "mem:<id>@<revision>", the
+// revision counting Unlocks so the canvas knows when to fetch the pixels again.
 std::string UIRenderTextureName(const CGraphicTexture* texture);
 
+// The pixels of memory texture "mem:<id>" (the part of the name before '@'), as 0xAARRGGBB.
+struct UIMemoryTexture {
+    int width = 0;
+    int height = 0;
+    std::uint32_t revision = 0;
+    std::vector<std::uint32_t> argb;
+};
+bool UIRenderMemoryTexture(const std::string& name, UIMemoryTexture* out);
+struct IDirect3DTexture8;
+void UIRenderReleaseMemoryTexture(IDirect3DTexture8* texture);
+
 // A textured quad from 40250's TPDTVertex[4] (TL, TR, BL, BR) positions and texture coordinates.
 // PORT: D3D8 puts pixel centres on integers, which is why 40250 subtracts 0.5 from every vertex; the
 // Godot canvas puts them on .5, so the quad is shifted back by +0.5 here.