Add AppBundleResourcePrefix property and update property precedence

Co-authored-by: rolfbjarne <249268+rolfbjarne@users.noreply.github.com>

Author: Copilot

dotnet/targets/Microsoft.Sdk.DefaultItems.template.props

@@ -59,7 +59,7 @@
 			<IsDefaultItem>true</IsDefaultItem>
 		</SceneKitAsset>
 
-		<!-- Include everything in the project's Resources folder (as represented by the _ResourcePrefix property, which is set from the IPhoneResourcePrefix/XamMacResourcePrefix properties),
+		<!-- Include everything in the project's Resources folder (as represented by the _ResourcePrefix property, which is set from the AppBundleResourcePrefix or legacy IPhoneResourcePrefix/XamMacResourcePrefix properties),
 		     except for files that are already in any of the other resource type item groups -->
 		<BundleResource Include="$(_ResourcePrefix)\**\*" Exclude="
 			$(DefaultItemExcludes);

msbuild/Xamarin.Shared/Xamarin.Shared.props

@@ -99,12 +99,20 @@ Copyright (C) 2020 Microsoft. All rights reserved.
 	<!-- Sometimes we've used different variable names for the same thing for Xamarin.iOS and Xamarin.Mac projects. Here we try to unify those variables -->
 	<PropertyGroup>
 		<!-- ResourcePrefix -->
+		<!-- AppBundleResourcePrefix is the unified property for all platforms (.NET) -->
+		<AppBundleResourcePrefix Condition="'$(AppBundleResourcePrefix)' == ''">Resources</AppBundleResourcePrefix>
+		<!-- Legacy properties for compatibility -->
+		<MonoMacResourcePrefix Condition="'$(_PlatformName)' == 'macOS' And '$(MonoMacResourcePrefix)' == '' And '$(AppBundleResourcePrefix)' != ''">$(AppBundleResourcePrefix)</MonoMacResourcePrefix>
 		<MonoMacResourcePrefix Condition="'$(_PlatformName)' == 'macOS' And '$(MonoMacResourcePrefix)' == ''">Resources</MonoMacResourcePrefix>
+		<XamMacResourcePrefix Condition="'$(_PlatformName)' == 'macOS' And '$(XamMacResourcePrefix)' == '' And '$(AppBundleResourcePrefix)' != ''">$(AppBundleResourcePrefix)</XamMacResourcePrefix>
 		<XamMacResourcePrefix Condition="'$(_PlatformName)' == 'macOS' And '$(XamMacResourcePrefix)' == ''">$(MonoMacResourcePrefix)</XamMacResourcePrefix>
 		<XamMacResourcePrefix Condition="'$(_PlatformName)' == 'macOS' And '$(XamMacResourcePrefix)' == ''">Resources</XamMacResourcePrefix>
+		<IPhoneResourcePrefix Condition="'$(_PlatformName)' != 'macOS' And '$(IPhoneResourcePrefix)' == '' And '$(AppBundleResourcePrefix)' != ''">$(AppBundleResourcePrefix)</IPhoneResourcePrefix>
 		<IPhoneResourcePrefix Condition="'$(_PlatformName)' != 'macOS' And '$(IPhoneResourcePrefix)' == ''">Resources</IPhoneResourcePrefix>
-		<_ResourcePrefix Condition="'$(_PlatformName)' == 'macOS'">$(XamMacResourcePrefix)</_ResourcePrefix>
-		<_ResourcePrefix Condition="'$(_PlatformName)' != 'macOS'">$(IPhoneResourcePrefix)</_ResourcePrefix>
+		<!-- Use AppBundleResourcePrefix if provided, otherwise fall back to platform-specific properties -->
+		<_ResourcePrefix Condition="'$(AppBundleResourcePrefix)' != ''">$(AppBundleResourcePrefix)</_ResourcePrefix>
+		<_ResourcePrefix Condition="'$(AppBundleResourcePrefix)' == '' And '$(_PlatformName)' == 'macOS'">$(XamMacResourcePrefix)</_ResourcePrefix>
+		<_ResourcePrefix Condition="'$(AppBundleResourcePrefix)' == '' And '$(_PlatformName)' != 'macOS'">$(IPhoneResourcePrefix)</_ResourcePrefix>
 
 		<!-- SdkVersion -->
 		<_SdkVersion Condition="'$(_PlatformName)' == 'macOS'">$(MacOSXSdkVersion)</_SdkVersion>