feat(locale)!: add Greek support and apply repo-wide hygiene updates

[ikramagix]

Summary

Add Greek locale support and perform repository-wide hygiene updates for v1.0.1.

Changes

• Add Greek (el) locale and extend name generation logic
• Refactor core data fetching and path handling
• Apply RuboCop formatting and add # frozen_string_literal: true
• Update specs to match formatting changes
• Bump version to 1.0.1 and update changelog
• Update CI to use main branch
• Bump Ruby target version to 2.7
• Add vendor directory
• Minor docs improvements (CONTRIBUTING, CHANGELOG)
• General cleanup (string quotes, trailing newline, etc.)

Rationale

Introduce new locale functionality while standardizing code style, improving maintainability, and aligning the project with current Ruby and CI conventions.

Testing

• Updated existing specs to reflect formatting and refactors
• All tests pass locally
• No regressions observed in existing functionality