[Bug] Auto-fix rewrites .env files with different line endings

## Describe the bug

The auto-fix functionality rewrites `.env` files using LF (`\n`) line endings.

On Windows projects that use CRLF, this results in unnecessary full-file diffs.

## Expected behavior

The original line ending style should be preserved when writing fixed .env files.

## Additional context

This occurs in fixEnv.ts inside the applyFixes function.
