migrate-mstest-v3-to-v4

Migrate an MSTest v3 test project to MSTest v4. Use when user says "upgrade to MSTest v4", "update to latest MSTest", "MSTest 4 migration", "MSTest v4 breaking changes", "MSTest v4 compatibility", or has build errors after updating MSTest packages from 3.x to 4.x. Also use for target framework compatibility (e.g. net6.0/net7.0 support with MSTest v4). USE FOR: upgrading MSTest packages from 3.x to 4.x, fixing source breaking changes (Execute -> ExecuteAsync, CallerInfo constructor, ClassCleanupBehavior removal, TestContext.Properties, Assert API changes, ExpectedExceptionAttribute removal, TestTimeout enum removal), resolving behavioral changes (TreatDiscoveryWarningsAsErrors, TestContext lifecycle, TestCase.Id changes, MSTest.Sdk MTP changes), handling dropped TFMs (net5.0-net7.0 dropped, only net8.0+, net462, uap10.0 supported). DO NOT USE FOR: migrating from MSTest v1/v2 to v3 (use migrate-mstest-v1v2-to-v3 first), migrating between test frameworks, or general .NET upgrades unrelated to MSTest.