Keep keyboard drag targets aligned with movement axis

packages/dnd/test/manager-lifecycle.test.ts

@@ -54,6 +54,7 @@ function fixture(overrides: Partial<DndManagerOptions> = {}) {
     manager,
     announcements,
     instances,
+    move: (code: string) => listeners.dragmove!({ nativeEvent: { code } }),
     start: (id: string) => listeners.dragstart!(event(id)),
     end: (id: string, target?: { id: string }) => listeners.dragend!({ ...event(id), operation: { ...event(id).operation, target } }),
     over: (target: { id?: string; group?: string; index?: number }) => {
@@ -94,6 +95,25 @@ test("late drop resolution cannot clear or announce a newer gesture", async () =
   ]);
 });
 
+test("keyboard candidates stay in the requested geometric row or column", () => {
+  const f = fixture();
+  const element = (left: number, top: number, right: number, bottom: number) => ({ getBoundingClientRect: () => ({ left, top, right, bottom }) }) as HTMLElement;
+  f.manager.registerSortable({ id: "source", group: "a", index: 0, element: element(0, 100, 100, 150) });
+  f.manager.registerDropZone({ id: "right", group: "b", index: 0, element: element(110, 100, 200, 160) });
+  f.manager.registerSortable({ id: "above", group: "c", index: 0, element: element(0, 0, 300, 90) });
+  const source = { id: "source", type: "text" };
+  f.start("source");
+  f.move("ArrowRight");
+  expect(f.instances[1]!.input.accept(source)).toBe(true);
+  expect(f.instances[2]!.input.accept(source)).toBe(false);
+  f.move("ArrowUp");
+  expect(f.instances[1]!.input.accept(source)).toBe(false);
+  expect(f.instances[2]!.input.accept(source)).toBe(true);
+  f.start("source");
+  expect(f.instances[2]!.input.accept(source)).toBe(true);
+  f.manager.destroy();
+});
+
 test("collision candidates exclude overlapping ancestors and invalid destinations before sorting", () => {
   const f = fixture({ accept: (_ids, to) => to.group !== "blocked" });
   const child = {} as HTMLElement;