Fix MAUI workload installation for platform-specific CI builds

[Copilot]

The generic maui workload fails on Ubuntu runners with "Workload ID maui isn't supported on this platform." Linux runners require platform-specific workloads.

Changes

• Android (Ubuntu): Install maui-android workload + Java SDK 11 setup
• Windows: Install maui-windows workload
• macOS: Install maui-maccatalyst and maui-ios workloads

Each runner now installs only the workloads it can support, eliminating the cross-platform workload installation failure.

Original prompt

Problem

The GitHub Actions workflow is failing with the error:

Workload installation failed: Workload ID maui isn't supported on this platform.

This occurs in the build-android job running on ubuntu-latest when executing dotnet workload install maui.

Root Cause

The full maui workload is not supported on Linux runners. For Android builds on Ubuntu, we need to install the platform-specific maui-android workload instead.

Required Changes

Update the .github/workflows/build.yml file to fix the workload installation for all three build jobs:

1. build-android job (lines 16-53)

• Change dotnet workload install maui to dotnet workload install maui-android
• Add Java SDK setup (required for Android builds)
• Consider using .NET 8.0.x instead of 10.0.x (as .NET 10 is not yet officially released)

2. build-windows job (lines 55-81)

• Change dotnet workload install maui to dotnet workload install maui-windows
• Consider using .NET 8.0.x instead of 10.0.x

3. build-macos job (lines 83-113)

• Change dotnet workload install maui to dotnet workload install maui-maccatalyst maui-ios
• Consider using .NET 8.0.x instead of 10.0.x

Additional Improvements

For the Android build job, add JDK setup before installing the MAUI workload:

- name: Setup JDK
  uses: actions/setup-java@v4
  with:
    distribution: 'microsoft'
    java-version: '11'

Expected Outcome

After these changes, the workflow should successfully install the platform-specific MAUI workloads and complete the builds for all three platforms (Android, Windows, and macOS).

This pull request was created from Copilot chat.

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