Add affected test selection to dotnet test

[Evangelink]

Summary

Adds an experimental, Microsoft.Testing.Platform-only affected-test workflow to dotnet test:

set DOTNET_CLI_ENABLE_AFFECTED_TESTS=1
dotnet test --collect-test-map
dotnet test --affected-tests

The SDK owns only the command-line and multi-module orchestration boundary. Repository analysis, test-map collection/storage, and affected-test filtering remain in a separately distributed MTP extension.

Relates to #55405. The composable MTP execution-filter API used by the extension was added by microsoft/testfx#10235.

Behavior

• Adds gated, localized --collect-test-map and --affected-tests options for the MTP runner.
• Keeps the operations mutually exclusive and rejects incompatible device, parallel-module, and minimum-test policies.
• Runs test-map collection one module at a time.
• Preserves forwarded argument ordering and validates recursive response files using each test application's effective working directory.
• Requires response-file activation to resolve consistently across all test applications.
• Marks SDK-launched children with DOTNET_CLI_TEST_AFFECTED_TESTS_MODE so the companion extension can reject activation injected through launch profiles, project run arguments, or test configuration.
• Treats a valid empty affected selection as success while preserving failure for all-skipped runs and unexpected process failures.
• Leaves ordinary dotnet test behavior unchanged when neither operation is requested.

Validation

• src/Cli/dotnet/dotnet.csproj builds with 0 warnings and 0 errors.
• test/dotnet.Tests/dotnet.Tests.csproj builds with 0 warnings and 0 errors.
• 123 targeted parser, launch-contract, terminal-reporting, and related command tests pass.
• Localization files regenerated with UpdateXlf.
• git diff --check passes.
• Six independent bug-focused review rounds were completed and all actionable findings were fixed.

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[Copilot]

Pull request overview

Adds an experimental, Microsoft.Testing.Platform-only affected-test workflow to dotnet test, gated behind DOTNET_CLI_ENABLE_AFFECTED_TESTS, with supporting validation, process-launch signaling, response-file detection, and terminal reporting changes.

Changes:

• Adds --collect-test-map / --affected-tests options (hidden unless enabled), with mutual-exclusion and incompatibility validation.
• Extends MTP orchestration to detect affected-test activation in forwarded response files and adjust behavior (e.g., collection forces single-module execution).
• Updates terminal reporting + exit-code behavior to allow “valid empty selection” in affected-test mode, with targeted regression tests.

Show a summary per file

File	Description
test/dotnet.Tests/CommandTests/Test/TestCommandParserTests.cs	Adds parser/normalization/response-file detection unit coverage for affected-test options.
test/dotnet.Tests/CommandTests/Test/TestApplicationLaunchTests.cs	Adds tests for affected-test option propagation and SDK “mode marker” environment variable behavior.
test/dotnet.Tests/CommandTests/Test/TerminalTestReporterTests.cs	Adds terminal-summary tests for allowed-zero-test behavior in affected-test mode.
test/dotnet.Tests/CommandTests/Test/MTPHelpSnapshotTests.cs	Stabilizes help snapshot by explicitly disabling affected-tests feature flag.
test/dotnet.Tests/CommandTests/Test/GivenDotnetTestSelectsDevice.cs	Adds validation test for --list-devices incompatibility with affected-test operations.
src/Cli/Microsoft.DotNet.Cli.Definitions/Commands/Test/TestCommandDefinition.MicrosoftTestingPlatform.cs	Introduces the two new options, feature gating, and definition-level validation.
src/Cli/Microsoft.DotNet.Cli.Definitions/CommandDefinitionStrings.resx	Adds localized source strings for new definition-level help/validation messages.
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.zh-Hant.xlf	Regenerated localization entries for new definition strings (zh-Hant).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.zh-Hans.xlf	Regenerated localization entries for new definition strings (zh-Hans).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.tr.xlf	Regenerated localization entries for new definition strings (tr).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.ru.xlf	Regenerated localization entries for new definition strings (ru).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.pt-BR.xlf	Regenerated localization entries for new definition strings (pt-BR).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.pl.xlf	Regenerated localization entries for new definition strings (pl).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.ko.xlf	Regenerated localization entries for new definition strings (ko).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.ja.xlf	Regenerated localization entries for new definition strings (ja).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.it.xlf	Regenerated localization entries for new definition strings (it).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.fr.xlf	Regenerated localization entries for new definition strings (fr).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.es.xlf	Regenerated localization entries for new definition strings (es).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.de.xlf	Regenerated localization entries for new definition strings (de).
src/Cli/Microsoft.DotNet.Cli.Definitions/xlf/CommandDefinitionStrings.cs.xlf	Regenerated localization entries for new definition strings (cs).
src/Cli/dotnet/Commands/Test/MTP/ITestHandler.cs	Extends handler contract to expose test-application working directories for response-file validation.
src/Cli/dotnet/Commands/Test/MTP/MSBuildHandler.cs	Implements working-directory enumeration for MSBuild-resolved test modules.
src/Cli/dotnet/Commands/Test/MTP/TestModulesFilterHandler.cs	Implements working-directory enumeration (fallback) for --test-modules flow.
src/Cli/dotnet/Commands/Test/MTP/Options.cs	Extends TestOptions with affected-test flags and forwarded-activation markers.
src/Cli/dotnet/Commands/Test/MTP/TestApplication.cs	Marks child processes with affected-test mode env var and preserves forwarded argument ordering.
src/Cli/dotnet/Commands/Test/MTP/MicrosoftTestingPlatformTestCommand.cs	Adds orchestration: validation, response-file detection, parallelism override for collection, and adjusted exit-code logic.
src/Cli/dotnet/Commands/Test/MTP/Terminal/TerminalTestReporterOptions.cs	Adds AllowZeroTests option to control summary semantics in affected-test mode.
src/Cli/dotnet/Commands/Test/MTP/Terminal/TerminalTestReporter.cs	Updates summary + per-assembly reporting to support allowed-zero-test runs and unexpected exit-code handling.
src/Cli/dotnet/Commands/CliCommandStrings.resx	Adds user-facing CLI validation strings for affected-test mode + response-file consistency.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.zh-Hant.xlf	Regenerated localization entries for new CLI strings (zh-Hant).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.zh-Hans.xlf	Regenerated localization entries for new CLI strings (zh-Hans).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.tr.xlf	Regenerated localization entries for new CLI strings (tr).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.ru.xlf	Regenerated localization entries for new CLI strings (ru).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.pt-BR.xlf	Regenerated localization entries for new CLI strings (pt-BR).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.pl.xlf	Regenerated localization entries for new CLI strings (pl).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.ko.xlf	Regenerated localization entries for new CLI strings (ko).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.ja.xlf	Regenerated localization entries for new CLI strings (ja).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.it.xlf	Regenerated localization entries for new CLI strings (it).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.fr.xlf	Regenerated localization entries for new CLI strings (fr).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.es.xlf	Regenerated localization entries for new CLI strings (es).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.de.xlf	Regenerated localization entries for new CLI strings (de).
src/Cli/dotnet/Commands/xlf/CliCommandStrings.cs.xlf	Regenerated localization entries for new CLI strings (cs).

Copilot's findings

• Files reviewed: 42/42 changed files
• Comments generated: 0