feat(website): Add Open Graph and Twitter Card meta tags for social sharing

[aaronpowell]

Summary

Adds Open Graph and Twitter Card meta tags to the website layout so pages render rich previews when shared on social media (Facebook, Twitter/X, LinkedIn, Discord, etc.).

Changes

website/src/layouts/BaseLayout.astro

• Added og:type, og:url, og:title, og:description, og:image, og:site_name meta tags
• Added twitter:card (summary_large_image), twitter:title, twitter:description, twitter:image meta tags
• Added canonical URL <link> element
• Changed title separator from - to | (e.g. Agents | Awesome GitHub Copilot)
• Uses new social-image.png from public/images/

website/src/scripts/modal.ts

• document.title updates dynamically when a modal opens to reflect the resource being viewed (e.g. Accessibility Expert | Awesome GitHub Copilot)
• Titles are resolved from JSON data files (agents.json, skills.json, etc.) using the resource's title property rather than the raw filename
• Handles skill/hook folder-path mismatches for correct title lookup
• Original page title is restored when the modal closes

website/public/images/social-image.png

• New social preview image for og:image / twitter:image tags

Testing

• npm run build and npx astro build both pass
• Verified OG tags appear correctly in built HTML output
• Line endings normalized

[Copilot]

Pull request overview

Adds social-sharing metadata (Open Graph + Twitter Card) to the Astro base layout and improves modal title handling so the browser tab title reflects the currently opened resource.

Changes:

• Added canonical link plus Open Graph and Twitter Card meta tags in the base layout (including a new social preview image URL).
• Updated the file modal to set/restore document.title and resolve human-friendly titles from generated JSON metadata.
• Added a new social-image.png under website/public/images/ for rich link previews.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 1 comment.

File	Description
website/src/layouts/BaseLayout.astro	Adds canonical + OG/Twitter meta tags and updates the page title format to use `
website/src/scripts/modal.ts	Dynamically updates/restores document.title and resolves modal titles from JSON metadata.
website/public/images/social-image.png	Adds a social preview image referenced by OG/Twitter meta tags.

[Copilot]

RESOURCE_TYPE_TO_JSON maps plugin -> plugins.json, but plugins.json items (generated by eng/generate-website-data.mjs) use name rather than title. As a result, resolveResourceTitle() can return undefined for plugins and briefly set title.textContent / document.title to undefined | Awesome GitHub Copilot when opening a plugin modal. Consider removing plugin from this lookup map (since openPluginModal() already sets the title), or special-casing plugins to read name (and updating the typed interface accordingly), or using a JSON source that actually contains a title field for plugins.

Suggested change

	plugin: "plugins.json",
	};
	};