feat: enhance README with demo video and promotional content

[markhallen]

• Add inline video demo section with HTML5 video tag and fallback link
• Enhance header with additional badges (Ruby version, Docker support)
• Improve tagline with compelling value proposition messaging
• Add Quick Start section for faster onboarding experience
• Expand Features section with detailed descriptions and benefits
• Include "Why Use This Tool?" section highlighting key advantages
• Reference live example in Issue Example issue #12 for real-world demonstration
• Restructure content flow for better user engagement and conversion

This significantly improves the project's presentation and should help
attract more users by clearly demonstrating the tool's value and
making the setup process appear more approachable.

Description

Brief description of the changes in this PR.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring/code cleanup

Testing

• Tests pass locally
• New tests added for new functionality
• Manual testing completed

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published

Additional Notes

Add any additional notes or context about the PR here.