Expose application artifacts

[Redth]

Apple platform builds and publishes now expose final artifacts through the shared @(ApplicationArtifact) item group. This gives custom targets and CI a stable way to discover .app, .ipa, .pkg, and .xcarchive outputs without parsing scalar properties, while leaving room for other platforms to use the same item group name.

Changes

• Add @(ApplicationArtifact) collectors for app bundles, IPA packages, PKG installers, and Xcode archives.
• Route Publish through GetApplicationArtifacts after _PrePublish, so publish-created artifacts run the same metadata extension path before Publish returns @(ApplicationArtifact).
• Add GetApplicationArtifactsDependsOn so later SDK layers such as .NET MAUI can enrich @(ApplicationArtifact) metadata before GetApplicationArtifacts or Publish returns.
• Route GetApplicationArtifacts through a mandatory private _CreateApplicationArtifacts target before extension targets run. That target runs Build plus the Apple app/package/archive producer targets so compiled outputs and platform artifacts exist before metadata enrichment.
• Keep the producer targets condition-gated by the existing Apple properties and target conditions such as BuildIpa, CreatePackage, ArchiveOnBuild, _CanArchive, and SdkIsDesktop, so querying artifacts does not unconditionally force IPA, PKG, or archive creation.
• Clarify that extension targets should update platform-created @(ApplicationArtifact) items when adding metadata, and only add new items for additional artifacts.
• Limit platform metadata to PackageFormat, IsDirectory, PlatformName, and BundleIdentifier.
• Update unit test assertions and in-repo build item/property/target docs for the new contract.
• Use dotnet build ... -getTargetResult examples for querying GetApplicationArtifacts and Publish results from the command line.
• Add direct item-query tests for IPA, PKG, app bundle, xcarchive outputs, extension metadata, publish-target metadata augmentation, overwritten GetApplicationArtifactsDependsOn behavior, and target dependency/condition-gate shape.

Validation

• xmllint --noout msbuild/Xamarin.Shared/Xamarin.Shared.targets msbuild/Xamarin.Shared/Xamarin.iOS.Common.targets dotnet/targets/Xamarin.Shared.Sdk.Publish.targets
• git diff --check
• make -C tests/dotnet/UnitTests build
• Attempted filtered extension-order tests locally; execution is blocked by missing Xcode/runtime/workload setup in this checkout.

[vs-mobiletools-engineering-service2]

✅ [PR Build #8beec2d] Build passed (Detect API changes) ✅

Pipeline on Agent
Hash: 8beec2d969368fb322fea3863327bd906ee3e310 [PR build]

[vs-mobiletools-engineering-service2]

✅ [PR Build #8beec2d] Build passed (Build packages) ✅

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Hash: 8beec2d969368fb322fea3863327bd906ee3e310 [PR build]

[vs-mobiletools-engineering-service2]

✅ API diff for current PR / commit

NET (empty diffs)

• iOS: vsdrops gist ( No breaking changes )
• tvOS: vsdrops gist ( No breaking changes )
• MacCatalyst: vsdrops gist ( No breaking changes )
• macOS: vsdrops gist ( No breaking changes )

✅ API diff vs stable

NET (empty diffs)

• iOS: vsdrops gist ( No breaking changes )
• tvOS: vsdrops gist ( No breaking changes )
• MacCatalyst: vsdrops gist ( No breaking changes )
• macOS: vsdrops gist ( No breaking changes )

ℹ️ Generator diff

Generator Diff: vsdrops (html) vsdrops (raw diff) gist (raw diff) - Please review changes)

Pipeline on Agent
Hash: 8beec2d969368fb322fea3863327bd906ee3e310 [PR build]

[vs-mobiletools-engineering-service2]

✅ [PR Build #8beec2d] Build passed (Build macOS tests) ✅

Pipeline on Agent
Hash: 8beec2d969368fb322fea3863327bd906ee3e310 [PR build]

[Redth]

Superseded by #25723, which uses the requested dev/redth/apple-artifacts-plan branch name.