fix: stop checklist toggles from dropping fast consecutive updates

TanStack Query v5 only runs a mutate() call's onSuccess for the latest
call on a shared observer, so checking two items before the first
request resolved silently dropped the first item's onItemUpdated call,
leaving the portal's checkbox out of sync with the server. Switch to
mutateAsync so each call's result is handled independently.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/v/[token]/dispatch/_components/checklist-section.tsx

@@ -22,10 +22,12 @@ export function ChecklistSection({
 
   const toggle = (item: VendorPortalChecklistItem) => {
     if (locked) return;
-    updateItem.mutate(
-      { itemId: item.id, isCompleted: !item.isCompleted },
-      { onSuccess: (updated) => onItemUpdated(updated) },
-    );
+    // mutateAsync resolves per call, unlike mutate's onSuccess which only fires for the
+    // latest call on this shared observer — needed so two quick toggles both report back.
+    void updateItem
+      .mutateAsync({ itemId: item.id, isCompleted: !item.isCompleted })
+      .then((updated) => onItemUpdated(updated))
+      .catch(() => undefined);
   };
 
   if (!items.length) {

src/test/app/v/checklist-section.test.tsx

@@ -67,4 +67,29 @@ describe("ChecklistSection", () => {
       await screen.findByText("Unable to update the checklist. Please try again."),
     ).toBeInTheDocument();
   });
+
+  it("reports every successful toggle when two items are checked before the first responds", async () => {
+    const a: VendorPortalChecklistItem = { id: 1, itemText: "Check filters", isCompleted: false };
+    const b: VendorPortalChecklistItem = { id: 2, itemText: "Check belts", isCompleted: false };
+    const resolvers: Array<() => void> = [];
+    vi.spyOn(vendorPortalApi, "updateChecklistItem").mockImplementation(
+      (_token, _dispatchId, itemId) =>
+        new Promise((resolve) => {
+          resolvers.push(() => resolve({ ...(itemId === 1 ? a : b), isCompleted: true }));
+        }),
+    );
+    const onItemUpdated = vi.fn();
+    renderSection({ items: [a, b] }, onItemUpdated);
+
+    const [boxA, boxB] = screen.getAllByRole("checkbox");
+    fireEvent.click(boxA);
+    fireEvent.click(boxB);
+
+    await waitFor(() => expect(resolvers).toHaveLength(2));
+    resolvers.forEach((resolve) => resolve());
+
+    await waitFor(() =>
+      expect(onItemUpdated.mock.calls.map(([updated]) => updated.id)).toEqual([1, 2]),
+    );
+  });
 });