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/third_party/CMakeLists.txt

@@ -37,6 +37,9 @@ add_library(mt3p::zstd ALIAS libzstd_static)
 # --- Crypto++ (MT_PROTOCOL=classic cipher) ----------------------------------
 add_subdirectory(cryptopp EXCLUDE_FROM_ALL)
 
+# --- FreeType (platform font adapter: EterLib/GrpFontTexture) ----------------
+add_subdirectory(freetype-2.13.3 EXCLUDE_FROM_ALL)
+
 # --- miniLZO ------------------------------------------------------------------
 # One translation unit, an amalgamation generated from the LZO sources. Its
 # public API (<lzo/lzo1x.h> via the shim header) is a strict subset of full LZO.