refactor: use detectExecutableType from @socketsecurity/lib and remove duplicates

- Replace manual file extension checks with detectExecutableType() for binary vs package detection
- Use detectExecutableType in spawnCoanaDlx, spawnCdxgenDlx, spawnSfwDlx, and spawnSocketPatchDlx
- Remove duplicate binary.mts (now in @socketsecurity/lib/dlx/binary)
- Remove duplicate detection.mts (now in @socketsecurity/lib/shadow and temporary-executor)
- Update imports to use @socketsecurity/lib versions
- Remove spawnNode usage in favor of direct spawn calls
- Remove dynamic spawn import
- Update test mocks to reference @socketsecurity/lib paths

This eliminates ~900 lines of duplicate code and provides more robust detection
using package.json, file extensions, and executable permissions.

Author: jdalton