[jonathanpeppers]

Missing ConfigureAwait(false) in reusable tooling can capture a caller's synchronization context. Enable CA2007 as an error for the AndroidSdk and BaseTasks libraries, retaining the existing suppression for application, installer, and test code. Existing library awaits already specify ConfigureAwait(false), so no runtime changes are needed. Intentional capture remains possible through explicit ConfigureAwait(true).

Fixes #12087

Validation:

• dotnet build src/Microsoft.Android.Build.BaseTasks/Microsoft.Android.Build.BaseTasks.csproj --nologo -v:minimal and dotnet build src/Xamarin.Android.Tools.AndroidSdk/Xamarin.Android.Tools.AndroidSdk.csproj --nologo -v:minimal: passed with zero warnings/errors. Temporarily adding an unconfigured await to each library caused its build to fail with CA2007, including in AndroidSdk's nested Runners/ directory; probes were removed afterward.
• dotnet test tests/Microsoft.Android.Build.BaseTasks-Tests/Microsoft.Android.Build.BaseTasks-Tests.csproj -v:minimal: 154 passed, 4 skipped.
• dotnet test tests/Xamarin.Android.Tools.AndroidSdk-Tests/Xamarin.Android.Tools.AndroidSdk-Tests.csproj --no-build -v:minimal -p:AndroidToolsDisableMultiTargeting=false -p:DotNetTargetFrameworkVersion=11.0 --filter 'FullyQualifiedName~AdbClientTests|FullyQualifiedName~AdbDeviceTrackerTests|FullyQualifiedName~AdbRunnerTests|FullyQualifiedName~AvdManagerRunnerTests|FullyQualifiedName~EmulatorRunnerTests|FullyQualifiedName~ProcessUtilsTests|FullyQualifiedName~DownloadUtilsTests|FullyQualifiedName~CommandLineToolsResolverTests' --blame-hang --blame-hang-timeout 60s --blame-hang-dump-type none: 269 passed.
• The broader AndroidSdk test command with the same framework properties built both netstandard2.0 and net11.0, but encountered a host JDK-discovery failure in Constructor_SetValuesFromPath. A non-integration rerun excluding that test passed 233 tests, skipped 1, then hit the 60-second inactivity limit in ChecksumOverrideDoesNotIgnoreInvalidHost(True). These unrelated discovery/installer issues were left unchanged.

[Copilot]

🟢 Approval recommended

There are no active review issues for the scoped CA2007 configuration change.

No open issues 🎉

What changed in this PR

Adds build-time enforcement of explicit ConfigureAwait usage in the shared Android tooling libraries, addressing #12087 without changing runtime code.

Changes:

• Enables CA2007 as an error for BaseTasks and AndroidSdk C# and VB files, including nested directories.
• Preserves existing analyzer defaults for application, installer, and test code.
• Allows intentional context capture through explicit ConfigureAwait(true).

File	Description
src/​.editorconfig	Adds a scoped CA2007 error rule for the two shared tooling libraries.

_{Review effort: Balanced}