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/port/EterLocale/StringCodec.h

@@ -0,0 +1,21 @@
+#pragma once
+
+int Ymir_WideCharToMultiByte(
+  UINT CodePage, 
+  DWORD dwFlags, 
+  LPCWSTR lpWideCharStr, 
+  int cchWideChar, 
+  LPSTR lpMultiByteStr, 
+  int cbMultiByte, 
+  LPCSTR lpDefaultChar, 
+  LPBOOL lpUsedDefaultChar 
+);
+
+int Ymir_MultiByteToWideChar(
+  UINT CodePage, 
+  DWORD dwFlags, 
+  LPCSTR lpMultiByteStr, 
+  int cbMultiByte, 
+  LPWSTR lpWideCharStr, 
+  int cchWideChar 
+);