"Backuper" is a spelling error. When adding "-er" to a word ending in a
consonant after a short vowel, the consonant is doubled: up → upper,
run → runner, backup → backupper.
Rather than "Backupper" (awkward), rename to "Creator" which:
- Is a real word
- Provides symmetry with BackupRestore::Restorer
- Matches naming patterns elsewhere (HostedSiteCreator, etc.)
BackupRestore::Backuper → BackupRestore::Creator