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/common/Win32Crt.h

@@ -83,4 +83,16 @@ void DeleteCriticalSection(LPCRITICAL_SECTION cs);
 void EnterCriticalSection(LPCRITICAL_SECTION cs);
 void LeaveCriticalSection(LPCRITICAL_SECTION cs);
 
+// stringapiset.h. WCHAR is 32-bit here, so wide strings hold UTF-32 code points. CP_UTF8 and
+// CP_ACP/1252 are converted directly; other code pages go through iconv where the platform has it.
+#define CP_ACP 0
+#define CP_UTF8 65001
+#define MB_PRECOMPOSED 0x00000001
+#define MB_ERR_INVALID_CHARS 0x00000008
+#define WC_NO_BEST_FIT_CHARS 0x00000400
+int MultiByteToWideChar(UINT CodePage, DWORD dwFlags, LPCSTR lpMultiByteStr, int cbMultiByte,
+                        LPWSTR lpWideCharStr, int cchWideChar);
+int WideCharToMultiByte(UINT CodePage, DWORD dwFlags, LPCWSTR lpWideCharStr, int cchWideChar,
+                        LPSTR lpMultiByteStr, int cbMultiByte, LPCSTR lpDefaultChar, LPBOOL lpUsedDefaultChar);
+
 #endif  // !_WIN32