Add Open Graph and Twitter Card meta tags for improved social sharing

[hxrshxz]

Fixes #3438

Changes

Added Open Graph and Twitter Card meta tags to enable social media preview cards

Verification

• No linting errors (npm run lint)
• No test errors (npm run test)
• Up to date with develop branch
• Descriptively named feature branch
• Meets accessibility guidelines

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Pull Request Overview

This PR adds Open Graph and Twitter Card meta tags to improve social media sharing previews for the p5.js Web Editor. When links are shared on platforms like Facebook, Twitter, or LinkedIn, these tags enable rich preview cards with titles, descriptions, and images.

• Added Open Graph meta tags (og:title, og:description, og:image, og:url, og:type) to both the main index and project-specific pages
• Added Twitter Card meta tags (twitter:card, twitter:title, twitter:description, twitter:image) to both page templates
• Customized the og:title and twitter:title for project pages to include the project name and username

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