- Added class methods to validate the format of strings for each field:
- `valid_name?` for surname, name, and patronymic (only letters allowed).
- `valid_phone_number?` for phone number (validates 10-15 digits, optional '+' sign).
- `valid_telegram?` for telegram handle (starts with '@' and allows letters, digits, and underscores).
- `valid_email?` for email (standard email format validation).
- `valid_git?` for Git link (validates GitHub URL format).
- Modified the `initialize` constructor:
- Integrated validations for all fields with descriptive error messages.
- Ensured objects cannot be created with invalid data formats.
Artem-Darius Weber