[codex] Skip Windows symlink tests without permission

[Star-Star66]

What changed

• Reuse the existing file-symlink capability probe across both version detection regression tests.
• Skip the npm install-prefix symlink test when Windows does not grant symlink creation permission.

Why

The install-source test already handled Windows environments without Developer Mode or elevated symlink privileges, but the related install-prefix test still called symlinkSync directly. That made the full verification suite fail with EPERM even though runtime behavior was not broken.

Impact

Windows contributors can run the full test suite without enabling symlink privileges. Environments that support symlinks still execute both regression tests normally.

Validation

• npm run verify
• 338 test files passed
• 3910 tests passed, 4 environment-related tests skipped

[Cyberforker]

Review Summary

Reviewed & merged by Carbon Code

Tests: npm run verify - 3910/3910 passed
Test: skip Windows symlink version checks when the environment lacks symlink permission.

Thanks @Star-Star66 for the small, targeted Windows test reliability fix.

Co-Authored-By: Carbon Code carboncode@code.ai6666.com

-- Carbon Code