Port Laravel's Contains and DoesntContain validation rules to Hypervel:

- Add Contains rule class for validating arrays contain required values
- Add DoesntContain rule class for validating arrays don't contain forbidden values
- Add validateDoesntContain() validator method
- Add Rule::contains(), Rule::doesntContain(), Rule::dateTime() static methods
- Add validation messages for 'can', 'contains', 'doesnt_contain'
- Full enum support (string-backed, int-backed, unit enums)
- Comprehensive tests for both rules