test(linter): cover unused directives with JS plugins in Vue (#26102)

## Summary

- Add an end-to-end regression fixture for unused disable directives in Vue files when a JavaScript plugin is enabled.
- Exercise the original #25892 source and snapshot the unused rule-name diagnostics instead of panicking.

## Testing

- Confirmed the same fixture aborts with the reported out-of-bounds panic on detached pre-fix commit 9d97da14c8.

Closes #25892
Closes #25922

Originally fixed by #25280.