Add native lazy-loading to BlogPostCard component to improve performance

[harnish7576]

Fixes #478

Description

• This PR improves Research page performance by enabling native lazy-loading for blog post images in BlogPostCard.

Modifications

• Previously, ~160 images loaded on page mount, causing high network usage and slower initial render. Adding loading="lazy" defers image loading until they enter the viewport, reducing initial load time while preserving layout stability due to the fixed-height image container.

Manual Browser Testing

• Only top-of-page images load initially.
• Additional image requests only fire when scrolling near them.

[vercel]

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