fix: resolve Windows CI segfaults from CRT mismatch and FreeType-HarfBuzz interaction

Three fixes for MSVC/clang-cl test crashes:

1. Set CMP0091 to NEW before project() so CMAKE_MSVC_RUNTIME_LIBRARY
   (static CRT /MT) takes effect for the top-level build.

2. Set CMAKE_POLICY_DEFAULT_CMP0091 NEW before each FetchContent subproject
   (FreeType, HarfBuzz) whose cmake_minimum_required resets the policy,
   preventing CRT mismatch between /MT and /MD that causes heap corruption.

3. Set FT_DISABLE_HARFBUZZ ON before building FreeType to prevent its
   find_package(HarfBuzz) from finding a partial match when HarfBuzz is
   also enabled, which would enable FT_CONFIG_OPTION_USE_HARFBUZZ inside
   FreeType and cause unresolved symbol crashes in test binaries.

Author: hypernewbie

CMakeLists.txt

@@ -1,5 +1,9 @@
 cmake_minimum_required(VERSION 3.21)
 
+if(POLICY CMP0091)
+    cmake_policy(SET CMP0091 NEW)
+endif()
+
 project(VEFontCache LANGUAGES C CXX)
 
 set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded")
@@ -22,6 +26,7 @@ set(VRHI_VERSION "v0.1.4" CACHE STRING "VRHI release version to fetch")
 include(FetchContent)
 
 if(VEFC_ENABLE_FREETYPE)
+    set(FT_DISABLE_HARFBUZZ ON CACHE BOOL "" FORCE)
     FetchContent_Declare(
         freetype
         GIT_REPOSITORY https://github.com/freetype/freetype.git
@@ -30,17 +35,21 @@ if(VEFC_ENABLE_FREETYPE)
     if(POLICY CMP0077)
         cmake_policy(SET CMP0077 NEW)
     endif()
+    set(CMAKE_POLICY_DEFAULT_CMP0091 NEW)
     FetchContent_MakeAvailable(freetype)
+    unset(CMAKE_POLICY_DEFAULT_CMP0091)
 endif()
 
 if(VEFC_ENABLE_HARFBUZZ)
+    set(CMAKE_POLICY_DEFAULT_CMP0091 NEW)
     FetchContent_Declare(
         harfbuzz
         GIT_REPOSITORY https://github.com/harfbuzz/harfbuzz.git
         GIT_TAG 11.2.1
     )
     set(HB_BUILD_SUBSET OFF CACHE BOOL "" FORCE)
     FetchContent_MakeAvailable(harfbuzz)
+    unset(CMAKE_POLICY_DEFAULT_CMP0091)
 endif()
 
 if(VEFC_BUILD_DEMO OR VEFC_BUILD_VRHI)