cleanup: remove Godot-era test data, formats/, dead proto reader and duplicates

- test/: bgfx/Godot render goldens and compare shots nothing reads any more;
  the Granny oracle result m2-numeric.json moves to oracle/
- formats/: only the .spt sniffer was still linked; it moves into
  platform/SpeedTreeLib, the rest and tools/map_probe go
- bgm/ duplicated Client/BGM byte for byte; tools/root archived root scripts
  that root.epk already holds; extension/src/proto had no build reference
- GEMINI.md duplicated AGENTS.md

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

extension/src/platform/CMakeLists.txt

@@ -10,8 +10,7 @@ if(NOT TARGET mtpython)
     list(FILTER MT_PLATFORM_SOURCES EXCLUDE REGEX "/ScriptLib/")
 endif()
 add_library(port_platform STATIC ${MT_PLATFORM_SOURCES})
-target_link_libraries(port_platform PUBLIC port_logic PRIVATE mt3p::freetype xrender::libgr2 xrender::formats)
-target_include_directories(port_platform PRIVATE ${CMAKE_SOURCE_DIR}/formats)
+target_link_libraries(port_platform PUBLIC port_logic PRIVATE mt3p::freetype xrender::libgr2)
 foreach(src IN LISTS MT_PLATFORM_SOURCES)
     mt_port_apply_defines(${src})
 endforeach()