feat(linter): Improve format check in linter

[aweell]

Pull Request Description: Improve Format Check in Linter

This pull request enhances the linter's functionality by introducing two distinct validation modes: format and contrast.

Motivation

The primary motivation behind this change is to improve the validation process for design tokens by providing clear and targeted checks. Previously, the linter was limited in its ability to validate token descriptions against palette references and ensure compliance with WCAG contrast standards. This update allows for a more structured approach to validation, enabling developers to focus on specific aspects of their tokens.

Key Improvements

1. Format Mode: This mode checks for:

   • Description Mismatches: Ensures that the description of each token matches its corresponding palette reference.
   • Invalid Palette References: Identifies any references to palette colors that do not exist.

2. Contrast Mode: This mode checks for:

   • WCAG Compliance: Validates that foreground and background color combinations meet the required contrast ratios, while skipping colors with alpha transparency and gradients.

3. Enhanced User Experience: The command-line interface has been updated to prompt users for the desired validation mode, making it easier to use the linter effectively without needing to remember specific command-line arguments.

4. Error Reporting: The linter now provides detailed error messages for both description mismatches and contrast failures, along with suggestions for alternative colors that meet contrast requirements.

By implementing these changes, this pull request significantly enhances the robustness of our linter, ensuring that our design tokens are both accurately described and compliant with accessibility standards. This ultimately leads to a more consistent and accessible user experience across our applications.