Switch LLM overview contact section from preview iframe to Quarto listing

[nrichers]

Pull Request Description

What and why?

Summary of changes

• Replaces the embedded page preview (::: {.preview source=...}) on the Large language model features page with a standard Quarto listing tile, consistent with other docs (for example deployment pages that link to the contact URL).
• Adds front matter listing configuration (id: llm-whats-next) with a single grid item: contact link, hero image, Request a demo title, and an LLM-focused description.
• Wires the third What's next column to :::{#llm-whats-next} and removes the obsolete HTML comment placeholder.

Before: The contact call-to-action used an iframe-style preview of validmind.com/contact. After: The same destination is presented as a listing card (same pattern as multi-tenant / VPV "request a demo" tiles), which avoids embedding the live site and matches site-wide listing usage.

How to test

Try the preview:

https://docs-staging.validmind.ai/pr_previews/fix-cookie-consent-banner-preview/about/overview-llm-features.html#whats-next

What needs special review?

• Copy on the listing description (LLM-focused line) and whether grid-columns: 1 in a narrow column looks acceptable on small viewports.

Dependencies, breaking changes, and deployment notes

• None.

Release notes

Documentation: the LLM features overview page now uses a contact Request a demo listing tile instead of an embedded page preview.

Checklist

• What and why
• Screenshots or videos (Frontend)
• How to test
• What needs special review
• Dependencies, breaking changes, and deployment notes
• Labels applied
• PR linked to Shortcut
• Unit tests added (Backend)
• Tested locally
• Documentation updated (if required)
• Environment variable additions/changes documented (if required)

[github-actions]

Pull requests must include at least one of the required labels: internal (no release notes required), highlight, enhancement, bug, deprecation, documentation. Except for internal, pull requests must also include a description in the release notes section.

[github-actions]

PR Summary

This PR introduces an enhancement to the large language model (LLM) features page by adding a new grid-based listing that highlights a call-to-action for requesting a demo. The changes include:

• The insertion of a new front matter section labeled 'listing' that configures a grid layout. This grid is defined with one column and no sorting, and it contains a single entry linking to the contact page.
• The listing entry includes details such as a path to the contact page, an image, a title ('Request a demo'), a brief description, and an author tag.
• The grid block is integrated within the existing page layout, replacing a previously commented-out section. This ensures the demo request is visually emphasized using the newly introduced grid styling and identifiers.

These modifications aim to improve user interaction by making it easier for visitors to request a demo of the LLM-powered platform.

Test Suggestions

• Verify the new grid listing renders correctly on the about page across various browsers and screen sizes.
• Click the 'Request a demo' link to ensure it navigates to the correct contact page.
• Ensure that the grid layout and its styling are responsive on mobile, tablet, and desktop devices.
• Check that the image and description load properly without causing layout issues.

[github-actions]

Validate docs site

✓ INFO: A live preview of the docs site is available — Open the preview

[validbeck]

Oops, I patched this in a PR with just buttons but I can't decide which version I like better. 🤔 Maybe a combination of both (Since the Legal Ease actually looks really... scuffed) if we're going with the tile...

I also kind of feel like the columns here don't make sense — for example, "request a demo" is the CTA for the 2nd column, but the tile itself is in a third column. I think it would make more sense to have "A commitment to transparency" (with the Legal Ease) button on it's own line ABOVE the "Try it yourself", then have the "Try it yourself" + demo CTA in the two column layout.

[validbeck]

Suggested change

	- path: https://validmind.com/contact/
	- path: https://validmind.com/request-demo/

[validbeck]

Hot take, this should actually take you to the request a demo page if we're going that route...

[nrichers]

Replaced by #1284.