feat: introduce hybrid input runtime

Add the process-wide hybrid input dispatcher, provider registry, PlayerLoop drain, focus-scoped input frames, and diagnostics.

Register the legacy provider and optional Unity Input System provider, migrate TextInput onto the dispatcher, and remove the old InputManagement path.

Add platform IME composition cancellation hooks, package the new Unity assembly roots, and document provider selection and IME behavior.

Author: LuviaDev

CMakeLists.txt

@@ -312,12 +312,18 @@ if (APPLE)
     find_library(CORESERVICES CoreServices)
     find_library(COREGRAPHICS CoreGraphics)
     find_library(METAL Metal)
+    if (NOT IOS)
+        find_library(APPKIT AppKit)
+    endif ()
     set(PROJECT_PLATFORM_LIBRARIES ${PROJECT_PLATFORM_LIBRARIES}
             "${FOUNDATION}" "${COREFOUNDATION}" "${CORETEXT}" "${CORESERVICES}" "${COREGRAPHICS}" "${METAL}")
+    if (APPKIT)
+        set(PROJECT_PLATFORM_LIBRARIES ${PROJECT_PLATFORM_LIBRARIES} "${APPKIT}")
+    endif ()
 endif ()
 
 if (WIN32)
-    set(PROJECT_PLATFORM_LIBRARIES ${PROJECT_PLATFORM_LIBRARIES} d3d12 dxgi d3dcompiler dwrite gdi32 ole32 uuid)
+    set(PROJECT_PLATFORM_LIBRARIES ${PROJECT_PLATFORM_LIBRARIES} d3d12 dxgi d3dcompiler dwrite gdi32 imm32 ole32 uuid)
 elseif (CMAKE_DL_LIBS)
     set(PROJECT_PLATFORM_LIBRARIES ${PROJECT_PLATFORM_LIBRARIES} ${CMAKE_DL_LIBS})
 endif ()
@@ -394,6 +400,8 @@ set(
         src/log/log.cpp
         src/log/log_unitylog.cpp
         src/io/milestro_io.cpp
+        src/ime/ImeSession_unsupported.cpp
+        src/ime/ImeSession_windows.cpp
 
         src/skia/FontFamilyKeywordMap.cpp
         src/skia/FontRegistry.cpp
@@ -423,10 +431,17 @@ set(
         src/unicode/util.cpp
 )
 
+if (APPLE)
+    list(APPEND MILESTRO_CORE_FILE
+            src/ime/ImeSession_ios.mm
+            src/ime/ImeSession_macos.mm)
+endif ()
+
 set(
         MILESTRO_APPLICATION_FILE
 
         src/game/milestro_game_plugin_main.cpp
+        src/game/milestro_game_ime.cpp
         src/game/milestro_game_unity_render.cpp
         src/unity_render/MilestroUnityRenderDispatcher.cpp
         src/unity_render/MilestroUnityRenderSubmissionDraw.cpp