feat(10-03): open, edit and save a record with toast and 422 feedback

- The SPA loads the backend::lang bundle before /auth/me, sets the
  document language from meta.locale and renders plural messages with
  Intl.PluralRules; interpolate mirrors phrasebook for :name/:Name/:NAME
- Create and record routes; mapWinterUrl maps recordUrl and redirects
  onto the controller's list, create and record routes only
- List rows open their record; FormView loads the form schema and the
  record, shows context-allowed fields in the span grid, saves values
  keyed by field name and toasts the resolved saved message
- A 422 puts each message under its field (aria-invalid,
  aria-describedby), shows the plural banner, focuses the first invalid
  field in schema order and clears a field's error on change
- The D-05 registry maps text, textarea, number and dropdown; any other
  type renders the unsupported-field box with the type in DM Mono
- The admin OpenAPI document declares the write request bodies
  (AdminRecord, AdminIDsRequest) and the list filter query as a
  deepObject, so the typed client can send them
- New backend::lang form.load_failed key; boardwalk/dist rebuilt

admin/tests/helpers.ts

@@ -0,0 +1,87 @@
+// Shared smoke-test helpers: a fetch mock keyed by "METHOD /path" and an app
+// mount at a route with a signed-in admin. Fixtures are neutral acme.demo.*
+// data; no application names appear in framework tests.
+import { vi } from 'vitest'
+import { flushPromises, mount } from '@vue/test-utils'
+import { createMemoryHistory } from 'vue-router'
+import App from '../src/App.vue'
+import { createAdminRouter } from '../src/app/router'
+import { me } from '../src/state/useAuth'
+import { loadNavigation } from '../src/state/useNavigation'
+import navigation from './fixtures/navigation.json'
+
+export const API = '/admin-test/api/v1'
+
+export const profile = {
+  data: {
+    id: 7,
+    login: 'dev',
+    email: 'dev@example.test',
+    first_name: 'Dana',
+    last_name: 'Dev',
+    is_superuser: false,
+    role: { id: 2, code: 'developer', name: 'Developer' },
+  },
+  meta: {},
+}
+
+export interface Reply {
+  status?: number
+  body: unknown
+}
+
+export type Route = Reply | ((request: Request) => Reply | Promise<Reply>)
+
+export function json(status: number, body: unknown): Response {
+  return new Response(JSON.stringify(body), { status, headers: { 'Content-Type': 'application/json' } })
+}
+
+export const notFound = { error: { code: 'not_found', message: 'Not found', details: {} } }
+
+/** Replaces fetch; routes are keyed by "METHOD pathname" (query ignored). */
+export function mockApi(routes: Record<string, Route>): Request[] {
+  const calls: Request[] = []
+  vi.spyOn(globalThis, 'fetch').mockImplementation(async (input: RequestInfo | URL) => {
+    const request = input as Request
+    calls.push(request)
+    const route = routes[`${request.method} ${new URL(request.url).pathname}`]
+    if (!route) {
+      return json(404, notFound)
+    }
+    const reply = typeof route === 'function' ? await route(request.clone()) : route
+    return json(reply.status ?? 200, reply.body)
+  })
+  return calls
+}
+
+export function pathOf(request: Request): string {
+  return new URL(request.url).pathname
+}
+
+export function queryOf(request: Request): URLSearchParams {
+  return new URL(request.url).searchParams
+}
+
+/** Requests matching a method and pathname, in call order. */
+export function requestsTo(calls: Request[], method: string, pathname: string): Request[] {
+  return calls.filter((request) => request.method === method && pathOf(request) === pathname)
+}
+
+/** Mounts the whole app at a path with the profile and navigation loaded. */
+export async function mountApp(path: string, routes: Record<string, Route>, options: { attach?: boolean } = {}) {
+  const calls = mockApi({
+    [`GET ${API}/auth/me`]: { body: profile },
+    [`GET ${API}/navigation`]: { body: navigation },
+    ...routes,
+  })
+  await me()
+  await loadNavigation()
+  const router = createAdminRouter(createMemoryHistory())
+  await router.push(path)
+  const wrapper = mount(App, {
+    global: { plugins: [router] },
+    attachTo: options.attach ? document.body : undefined,
+  })
+  await flushPromises()
+  return { wrapper, calls, router }
+}