feat(12.2-04): edit related records in modals and defer relation work on new records

- RelationManager renders create/link/delete/unlink in declared order with
  one primary, opens the child modal (update or view form) or the pivot
  modal on row click, and deletes selected children behind a busy confirm
- RelationChildModal creates and edits children with its own session key
  (X-Child-Session-Key) so uploads and dates work inside it
- RelationPivotModal edits link details; the picker links one record with
  its pivot values when the relation has a pivot form
- deferrable managers render on the create screen with owner id 0, the
  form's X-Session-Key and the pending note, and mark the form dirty
- the registry resolves RelationManager lazily (child forms close an
  import cycle); DataTable gains openable rows and a trailing cell
- relation lang keys in en and pl; rebuilt boardwalk dist

admin/tests/relation/RelationManager.test.ts

@@ -150,3 +150,77 @@ describe('relation manager (D-05, design screen 5)', () => {
     expect(wrapper.find('[data-action="unlink"]').attributes('disabled')).toBeUndefined()
   })
 })
+
+describe('relation manager child editing (Phase 12.2, D-11, D-12)', () => {
+  const editable = {
+    ...relationSchemaFixture,
+    data: {
+      ...relationSchemaFixture.data,
+      view: { ...relationSchemaFixture.data.view, toolbarButtons: ['create', 'update', 'delete', 'link'] },
+      manageForm: [{ name: 'name', label: 'Name', type: 'text' }],
+    },
+  }
+  const RECORDS = `${LINKED}/records`
+  const DELETE = `${LINKED}/delete`
+
+  it('renders the toolbar in order with create as the only primary button', async () => {
+    const { wrapper } = await mountManager({ [`GET ${SCHEMA}`]: { body: editable } })
+    const actions = wrapper.findAll('header [data-action]').map((button) => button.attributes('data-action'))
+    expect(actions).toEqual(['create', 'delete', 'link'])
+    expect(wrapper.find('[data-action="link"]').classes()).not.toContain('bg-primary')
+    expect(wrapper.find('[data-action="create"]').classes()).toContain('bg-primary')
+  })
+
+  it('opens the child modal in update mode from the row button and saves the child', async () => {
+    const first = linkedFixture.all.data[0]!
+    const { calls } = await mountManager({
+      [`GET ${SCHEMA}`]: { body: editable },
+      [`GET ${RECORDS}/${first.id}`]: { body: { data: { ...first }, meta: { labels: {} } } },
+      [`PUT ${RECORDS}/${first.id}`]: { body: { data: { ...first }, meta: { labels: {} } } },
+    })
+    ;(document.body.querySelector('[data-row-open]') as HTMLButtonElement).click()
+    await flushPromises()
+    const modal = document.body.querySelector<HTMLElement>('[data-relation-child-modal]')!
+    expect(modal.dataset.mode).toBe('update')
+    const input = modal.querySelector<HTMLInputElement>('#child-members-name')!
+    expect(input.value).toBe(String(first.name))
+    input.value = 'Renamed'
+    input.dispatchEvent(new Event('input'))
+    await flushPromises()
+    ;(modal.querySelector('[data-action="save-child"]') as HTMLButtonElement).click()
+    await flushPromises()
+    const [put] = requestsTo(calls, 'PUT', `${RECORDS}/${first.id}`)
+    expect(await put!.clone().json()).toEqual({ name: 'Renamed' })
+    expect(put!.headers.get('X-Child-Session-Key')).toMatch(/^[A-Za-z0-9_-]{43}$/)
+    expect(document.body.querySelector('[data-relation-child-modal]')).toBeNull()
+  })
+
+  it('closes, toasts and reloads when the child is gone', async () => {
+    const first = linkedFixture.all.data[0]!
+    const { calls } = await mountManager({
+      [`GET ${SCHEMA}`]: { body: editable },
+      [`GET ${RECORDS}/${first.id}`]: failure(404, 'Not found'),
+    })
+    ;(document.body.querySelector('[data-row-open]') as HTMLButtonElement).click()
+    await flushPromises()
+    expect(document.body.querySelector('[data-relation-child-modal]')).toBeNull()
+    expect(toasts.value[0]).toMatchObject({ text: 'backend::lang.relation.child_gone', tone: 'danger' })
+    expect(requestsTo(calls, 'GET', LINKED)).toHaveLength(2)
+  })
+
+  it('deletes the selected children after a confirmation and keeps them on failure', async () => {
+    const { wrapper, calls } = await mountManager({
+      [`GET ${SCHEMA}`]: { body: editable },
+      [`POST ${DELETE}`]: failure(422, 'Refused'),
+    })
+    expect(wrapper.find('[data-action="delete"]').attributes('disabled')).toBeDefined()
+    await wrapper.find('tbody [role="checkbox"]').trigger('click')
+    await wrapper.find('[data-action="delete"]').trigger('click')
+    await flushPromises()
+    ;(document.body.querySelector('[data-confirm-dialog] [data-action="confirm"]') as HTMLElement).click()
+    await flushPromises()
+    expect(requestsTo(calls, 'POST', DELETE)).toHaveLength(1)
+    expect(toasts.value[0]).toMatchObject({ text: 'Refused', tone: 'danger' })
+    expect(wrapper.find('tbody [role="checkbox"]').attributes('aria-checked')).toBe('true')
+  })
+})