Add og:image:type meta tag to social cards

[IEvangelist]

Summary

Adds the optional og:image:type Open Graph meta tag to every page's social card so crawlers can validate and decode the image by its advertised MIME type without content sniffing.

<meta property="og:image:type" content="image/png" />

Details

OG image tags on aspire.dev are generated (Astro + Starlight), not hardcoded per page, so the fix lives in the metadata pipeline:

• src/utils/page-metadata.ts — added an imageType field to OgMetadata and a resolveOgImageType() helper that infers the MIME type from the resolved og:image URL extension. Defaults to image/png (covering the dynamic /og/<slug>.png cards and the /og-image.png fallback) and also maps jpeg/webp/gif/svg/avif for any ogImage frontmatter override. Case-insensitive; ignores query strings and fragments.
• src/components/starlight/Head.astro — emits <meta property="og:image:type" content={ogMetadata.imageType} /> immediately after og:image.
• config/head.attrs.ts — updated the doc comment listing the per-page OG tags.

Tests

• Unit (tests/unit/page-metadata.vitest.test.ts) — new resolveOgImageType suite (extension mapping, case-insensitivity, query/fragment handling, unknown/missing-extension fallback) plus getOgMetadata assertions for PNG and a non-PNG override.
• E2E (tests/e2e/og-metadata.spec.ts) — asserts og:image:type = image/png on the dynamic-card and sample pages.

[Copilot]

Pull request overview

Adds support for the optional Open Graph meta tag og:image:type across aspire.dev’s generated social metadata so crawlers can interpret the image MIME type without sniffing.

Changes:

• Extend the OG metadata pipeline with an imageType field and a resolveOgImageType() helper that infers MIME type from the og:image URL (defaulting to image/png).
• Emit <meta property="og:image:type" ...> in the Starlight head wrapper alongside existing og:image tags.
• Add unit and e2e coverage to validate the inferred MIME type and emitted meta tag.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/frontend/src/utils/page-metadata.ts	Adds OgMetadata.imageType and resolveOgImageType(); wires imageType into getOgMetadata().
src/frontend/src/components/starlight/Head.astro	Emits the og:image:type meta tag next to og:image.
src/frontend/config/head.attrs.ts	Updates the documentation comment listing dynamically emitted per-page OG tags.
src/frontend/tests/unit/page-metadata.vitest.test.ts	Adds unit tests for MIME-type inference and getOgMetadata().imageType.
src/frontend/tests/e2e/og-metadata.spec.ts	Adds e2e assertions that og:image:type is present and image/png for key pages.

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[aspire-repo-bot]

Frontend HTML artifact ready

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