Filter invalid Windows env var names before passing to child_process

[Copilot]

Windows environment variables like CommonProgramFiles(x86) and ProgramFiles(x86) contain parentheses, which newer Node.js versions reject when passed via options.env to child_process.exec, causing SDK installs to fail with options.env has an invalid environment variable name: "CommonProgramFiles(x86)".

Changes

• TypescriptUtilities.ts: Added isValidEnvironmentVariableName(name) and filterEnvVars(env) — filters out env vars whose names contain parentheses (the character class Node.js rejects in options.env)
• CommandExecutor.ts: Apply filterEnvVars() in both code paths where process.env is spread into options.env

// Before
options.env ??= { ...process.env };

// After
options.env ??= filterEnvVars({ ...process.env });

• TypescriptUtilities.test.ts: Unit tests covering both isValidEnvironmentVariableName and filterEnvVars for the parentheses case and standard valid names

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• microsoft.com
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node node /home/REDACTED/work/vscode-dotnet-runtime/vscode-dotnet-runtime/vscode-dotnet-runtime-library/node_modules/.bin/mocha -u tdd -- dist/test/unit/DebianDistroTests.test.js dist/test/unit/DotnetConditionValidator.test.js dist/test/unit/DotnetCoreAcquisitionWorker.test.js dist/test/unit/DotnetPathFinder.test.js dist/test/unit/DotnetResolver.test.js dist/test/unit/ErrorHandler.test.js dist/test/unit/ExecutableArchitectureDetector.test.js dist/test/unit/ExistingPathResolver.test.js dist/test/unit/FileUtilities.test.js dist/test/unit/GlobalInstallerResolver.test.js dist/test/unit/InstallScriptAcquisitionWorker.test.js dist/test/unit/InstallTracker.test.js dist/test/unit/InstallationValidator.test.js dist/test/unit/IssueReporter.test.js dist/test/unit/JsonInstaller.test.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)