feat(web): useSetVisibility hook + adjacentTransitions helper + MSW handler

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/src/api/queries.visibility.test.tsx

@@ -0,0 +1,38 @@
+import { describe, expect, test } from "vitest";
+import { renderHook } from "@testing-library/react";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { http, HttpResponse } from "msw";
+import type { ReactNode } from "react";
+
+import { server } from "../test/server";
+import { useSetVisibility } from "./queries";
+
+function wrapper({ children }: { children: ReactNode }) {
+  const qc = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+  return <QueryClientProvider client={qc}>{children}</QueryClientProvider>;
+}
+
+describe("useSetVisibility", () => {
+  test("POSTs the target visibility and resolves on 204", async () => {
+    let body: unknown;
+    server.use(
+      http.post("/api/admin/objects/:id/visibility", async ({ request }) => {
+        body = await request.json();
+        return new HttpResponse(null, { status: 204 });
+      }),
+    );
+    const { result } = renderHook(() => useSetVisibility(), { wrapper });
+    await result.current.mutateAsync({ id: "o1", visibility: "internal" });
+    expect((body as { visibility: string }).visibility).toBe("internal");
+  });
+
+  test("throws a status-carrying error on 422 (publish gate)", async () => {
+    server.use(
+      http.post("/api/admin/objects/:id/visibility", () => new HttpResponse(null, { status: 422 })),
+    );
+    const { result } = renderHook(() => useSetVisibility(), { wrapper });
+    await expect(
+      result.current.mutateAsync({ id: "o1", visibility: "public" }),
+    ).rejects.toMatchObject({ status: 422 });
+  });
+});