MediaAccessibility tvOS xcode27.0 b1

#MediaAccessibility.framework https://github.com/dotnet/macios/pull/26172

diff -ruN /Applications/Xcode_26.5.0.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS.sdk/System/Library/Frameworks/MediaAccessibility.framework/Headers/MACaptionAppearance.h /Applications/Xcode_27.0.0-beta.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS.sdk/System/Library/Frameworks/MediaAccessibility.framework/Headers/MACaptionAppearance.h
--- /Applications/Xcode_26.5.0.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS.sdk/System/Library/Frameworks/MediaAccessibility.framework/Headers/MACaptionAppearance.h	2026-04-18 19:12:09
+++ /Applications/Xcode_27.0.0-beta.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS.sdk/System/Library/Frameworks/MediaAccessibility.framework/Headers/MACaptionAppearance.h	2026-05-23 02:28:10
@@ -40,6 +40,7 @@
 {
     kMACaptionAppearanceDomainDefault = 0,
     kMACaptionAppearanceDomainUser = 1,
+    kMACaptionAppearanceDomainVideoConferencing API_AVAILABLE(macos(27.0), ios(27.0)) = 2
 } CF_ENUM_AVAILABLE(10_9, 7_0);
 
 /*!