Adds a copy-to-clipboard button for code blocks in the documentation to improve developer experience.

[Rishi2600]

Fixes #645

Changes

• Added a copy button that appears on hover over code blocks
• Implemented clipboard functionality with fallback support for older browsers
• Added visual feedback ("Copied!" confirmation message)
• Styled with Primer CSS design conventions
• Mobile-friendly (always visible on touch devices)

Implementation

• Created js/copy-code.js with copy functionality and button creation logic
• Created assets/css/copy-code.css with styling for the copy button
• Updated _layouts/default.liquid to include the new CSS and JS files

For any feature updates or any other details, Contact - github.com/Rishi2600