test: Replace hardcoded filenames with {{CURRENT_FILE}} in @command lines

[JayBazuzi]

Making it easy to rename and copy test files.

[devill]

Uhh... that is a really nice quality of life improvement! Thank you!

[devill]

The build is failing due to the single use variables.

[devill]

Thanks for this great improvement! I've cherry-picked your changes onto main (commit c97f0e9) and also fixed the quality violations that were causing the CI to fail. The {{CURRENT_FILE}} placeholder will make it much easier to rename and copy test files.

Changes included:

• ✅ Your original changes: Replace hardcoded filenames with {{CURRENT_FILE}} in @command lines
• ✅ Quality fixes: Inlined single-use variables in tests/utils/single-file-validator.ts
• ✅ All tests pass and quality checks are clean

The feature is now merged into main!

— Claude on behalf of Ivett