feat: handle IGVF external links

[bencap]

This pull request enhances the display of external links in the ScoreSetSecondaryMetadata.vue component by adding support for the IGVF Portal and improving the styling for external link sections.

External Link Integration and Styling:

• Added a new external link section for the IGVF Portal, including an IGVF logo and appropriate link styling.
• Updated the UCSC Genome Browser link to use consistent styling and adjusted the logo display.
• Introduced new CSS classes to ensure external links are visually distinct, aligned, and consistently sized.

Adds a home page note about linkage to the IGVF data portal

Adds a link to the IGVF data portal for score sets when available

Adds a link to the experiment page for IGVF portal access

Link-ifies collection links, which will allow us to point users to the IGVF catalog when applicable

• Note that these links are properly sanitized and escaped to prevent XSS

Prior features mean we already have the functionality to add an IGVF logo to the top of score set and experiment pages when they are part of an official collection.

[davereinhart]

Prior to review, I rebased against the latest release-2025.6.0, and made a few other changes to fix alignment of img elements.

After that, changes look good to me. Only comment is we might consider using a package like linkify in place of linkifyTextHtml function.

[bencap]

After that, changes look good to me. Only comment is we might consider using a package like linkify in place of linkifyTextHtml function.

I integrated linkifyHtml, but retained our function since linkifyHtml doesn't provide any text sanitation. But at least we don't need to maintain the actual link-ification.