A card's logo is its handle. A grip shows by it only while the pointer is on the card, as on Agents and Providers. The card is dragged across the grid: dragCards is dragRows in two directions, the slot nearest its middle is where it goes, and the cards between move a slot over. Alt+arrows move it from the keyboard and keep the focus on it. The order is settings usageOrder, by provider id, saved by POST /api/usage/arrange. It is apart from the Providers order, which is also the order providers are tried in. POST /api/settings keeps it. A card it doesn't name follows in magpie's own order, and an order naming one not on the page now keeps it after them. The tray panel's Usage tab follows the same order.
usage-arrange.test.cjs covers the hover-only grip, a drag across the grid, Alt+arrows, a click that moves nothing, the order after a reload, and the panel. It passes in Chromium and WebKit, en and zh. TestSettingsSaveKeepsWhatItDoesNotSend covers usageOrder. go test ./internal/gui ./internal/settings under a temp HOME, go vet, and builds (darwin, GOOS=linux, GOOS=windows) pass. Also tried on a sandbox magpie web with faked quotas: the drag, the keyboard and a reload kept the order in WebKit and Chromium. The other Usage/panel UI tests pass, except credit-days.test.cjs, which fails about 1 run in 4 on main too.