Forage detail page splits metadata and body into separate cards

The forage item detail page now shows metadata and rendered body content as two separate sibling cards instead of packing both into one combined card. The first card is now the Metadata card with source, requester, updated date, and domain badges, and the rendered item body lives in its own Details card below it. While an item is being edited, the form stays in the first card (labeled “Edit item”) and the body card is hidden so the page does not duplicate content. The new structure is shared across manual forage items, GitHub issues, and Grafana alerts, and it improves scanning on long Markdown bodies (such as seeded GitHub issues) at desktop and mobile widths.