Drop detail page metadata moved into its own card

Drop detail pages now display source, version, domain, publication date, and repository fields in a dedicated Metadata card placed between the drop title and the update body. The page hierarchy is clearer: title and Open original action first, the new metadata card second, and update content third. The layout also groups these fields into the same metadata grid pattern used on other detail pages in Hive, with responsive stacking on narrow screens, making drop pages easier to scan as they accumulate more context.