Bug: Gemspec sets authors twice, missing email field

## Description
`paper_trail_manager.gemspec` overwrites `spec.authors` with an email address on the second line. Should be `spec.email`.

## Acceptance Criteria
- [ ] `spec.authors` lists actual authors (Igal Koshevoy, Reid Beels, Tony Guntharp)
- [ ] `spec.email` is set correctly
- [ ] `gem build` produces valid gemspec