chore(demo): conditionally add iOS target on macOS only

Author: fadi-george

.github/workflows/e2e.yml

@@ -45,8 +45,15 @@ jobs:
         with:
           dotnet-version: '10.0.x'
 
-      - name: Install MAUI Android workload
-        run: dotnet workload install maui-android
+      # Install both maui-android and maui-ios. The OneSignal library projects
+      # are multi-targeted (net10.0;net10.0-android;net10.0-ios;netstandard2.0),
+      # and NuGet restore walks every declared TargetFramework of transitively
+      # referenced projects. Without the iOS workload pack on disk, restoring
+      # the iOS TFM of OneSignalSDK.DotNet/iOS/iOS.Binding fails with NETSDK1178
+      # even though we only build the android TFM. The actual iOS build never
+      # runs here; we just need the workload pack present for restore.
+      - name: Install MAUI workloads
+        run: dotnet workload install maui-android maui-ios
 
       - name: Create demo .env
         working-directory: examples/demo
@@ -103,8 +110,12 @@ jobs:
         with:
           dotnet-version: '10.0.x'
 
-      - name: Install MAUI iOS workload
-        run: dotnet workload install maui-ios
+      # See note in build-android job: both workloads are required even though
+      # only the iOS TFM is built, because restore walks the multi-targeted
+      # library projects and the android TFM follows references into the
+      # android-only OneSignalSDK.DotNet.Android* projects.
+      - name: Install MAUI workloads
+        run: dotnet workload install maui-android maui-ios
 
       - name: Create demo .env
         working-directory: examples/demo

examples/demo/demo.csproj

@@ -1,6 +1,14 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>net10.0-android;net10.0-ios</TargetFrameworks>
+    <!--
+      iOS targets only on macOS hosts. Linux/Windows CI runners (e.g. the
+      Android build job) don't have the iOS workload installed, and NuGet
+      restore evaluates every declared TargetFramework, which would otherwise
+      pull in NotificationServiceExtension.csproj (net10.0-ios) and fail with
+      NETSDK1178 looking for Microsoft.iOS.Sdk.
+    -->
+    <TargetFrameworks>net10.0-android</TargetFrameworks>
+    <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('OSX'))">$(TargetFrameworks);net10.0-ios</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>OneSignalDemo</RootNamespace>
     <UseMaui>true</UseMaui>