Manually curated links at top

We should add the possibility to add manually curated items (tiles) at the top of the page.

This is useful, for example, to pin workshop announcements (AI workshop), or other information relevant to visitors.

The issue names no files, tests, or entry points. Start by locating the page that renders the current tiles and how its content is sourced; clarify the intended tile fields and ordering before implementing. Done means manually curated items can be configured, appear at the top, and support announcements such as the AI workshop.

Written by the indexing model from the issue text.