fix(17): WR-02 keep one reorder save in flight and ignore stale responses

A move made while a save runs is queued and sent after it settles, so
out-of-order completion can no longer leave the database on an older tree
than the screen. A failure that a waiting save supersedes keeps the later
moves, and a response tied to an earlier load or partition leaves the
current tree and its last saved state alone.

admin/tests/views/ReorderView.test.ts

@@ -318,6 +318,94 @@ describe('ReorderView moves', () => {
   })
 })
 
+// WR-02: one save in flight at a time, later moves sent after it settles,
+// and a failure that a waiting save supersedes does not throw moves away.
+describe('ReorderView save ordering', () => {
+  it('sends a move made during a save after that save, with the latest tree', async () => {
+    const bodies: { nodes: { id: number }[] }[] = []
+    const releases: ((reply: Reply) => void)[] = []
+    const { wrapper, calls } = await mountApp(
+      '/acme/companions/links/reorder',
+      {
+        [`GET ${REORDER}`]: tree(),
+        [`POST ${REORDER}`]: async (request) => {
+          bodies.push((await request.json()) as { nodes: { id: number }[] })
+          return new Promise<Reply>((resolve) => releases.push(resolve))
+        },
+      },
+      { attach: true },
+    )
+    keydown(handle(wrapper, 1).element, 'ArrowDown')
+    await flushPromises()
+    await vi.waitFor(() => expect(requestsTo(calls, 'POST', REORDER)).toHaveLength(1))
+
+    // A second move while the first save is in flight waits for it.
+    keydown(handle(wrapper, 4).element, 'ArrowUp')
+    await flushPromises()
+    await wait(500)
+    expect(requestsTo(calls, 'POST', REORDER)).toHaveLength(1)
+
+    // The first save fails: the later moves stay on screen, and the waiting
+    // save sends them.
+    releases[0]!({ status: 500, body: { error: { code: 'x', message: 'x', details: {} } } })
+    await vi.waitFor(() => expect(requestsTo(calls, 'POST', REORDER)).toHaveLength(2))
+    expect(shape(wrapper)).toBe('Blog(News) Bez tytułu (#4) Home')
+    expect(toasts.value).toHaveLength(0)
+    expect(bodies[1]!.nodes.map((node) => node.id)).toEqual([2, 3, 4, 1])
+    releases[1]!(tree())
+    await vi.waitFor(() => {
+      expect(wrapper.find('[data-reorder-status]').text()).toBe('Zapisano kolejność')
+    })
+    expect(shape(wrapper)).toBe('Blog(News) Bez tytułu (#4) Home')
+    await wait(500)
+    expect(requestsTo(calls, 'POST', REORDER)).toHaveLength(2)
+  })
+
+  it('ignores a save response that arrives after the partition changed', async () => {
+    let releaseFirst: (reply: Reply) => void = () => undefined
+    let posts = 0
+    const footer = tree()
+    ;(footer.body as { data: { nodes: unknown[] } }).data.nodes = [
+      { id: 7, name: 'Imprint', parent_id: null, sort_order: 1 },
+      { id: 8, name: 'Privacy', parent_id: null, sort_order: 2 },
+    ]
+    const { wrapper } = await mountApp(
+      '/acme/companions/links/reorder',
+      {
+        [`GET ${REORDER}`]: (request) => (queryOf(request).get('partition') === '6' ? footer : tree()),
+        [`POST ${REORDER}`]: () => {
+          posts++
+          if (posts === 1) {
+            return new Promise<Reply>((resolve) => {
+              releaseFirst = resolve
+            })
+          }
+          return { status: 500, body: { error: { code: 'x', message: 'x', details: {} } } }
+        },
+      },
+      { attach: true },
+    )
+    keydown(handle(wrapper, 1).element, 'ArrowDown')
+    await flushPromises()
+    await wrapper.find('[data-reorder-partition]').setValue('6')
+    await flushPromises()
+    await vi.waitFor(() => expect(shape(wrapper)).toBe('Imprint Privacy'))
+
+    // The first partition's save succeeds late: the second partition's
+    // screen and its last saved tree are not touched.
+    releaseFirst(tree())
+    await flushPromises()
+    expect(shape(wrapper)).toBe('Imprint Privacy')
+
+    // A failed save on the second partition restores its own tree.
+    keydown(handle(wrapper, 7).element, 'ArrowDown')
+    await flushPromises()
+    expect(shape(wrapper)).toBe('Privacy Imprint')
+    await vi.waitFor(() => expect(toasts.value.length).toBeGreaterThan(0))
+    expect(shape(wrapper)).toBe('Imprint Privacy')
+  })
+})
+
 describe('reorder tree rules', () => {
   // The OpenAPI document types parent_id as a number although the wire
   // carries null at the top (17-02 deferred item 3), hence the cast.