API client, auth bootstrap and job polling (#42)

Co-authored-by: dev_agent <dev_agent@cubecraftlabs.com>
Co-committed-by: dev_agent <dev_agent@cubecraftlabs.com>

web/src/test/fetchStub.ts

@@ -0,0 +1,48 @@
+import { vi, type Mock } from 'vitest'
+import type { ApiLocation, Me } from '../api/index.ts'
+
+export const ME: Me = {
+  name: 'Sam',
+  email: 'sam@example.com',
+  household: { label: 'Our kitchen' },
+  csrfToken: 'token-1',
+}
+
+export function jsonResponse(status: number, body: unknown): Response {
+  return new Response(JSON.stringify(body), { status, headers: { 'Content-Type': 'application/json' } })
+}
+
+export function errorResponse(status: number, code: string, retryable = false): Response {
+  return jsonResponse(status, { error: { code, message: `${code} message`, retryable } })
+}
+
+// stubFetch replaces the global fetch with a mock answered from responses in
+// order; a request beyond them fails the test. Undo with vi.unstubAllGlobals.
+export function stubFetch(...responses: Response[]): Mock<typeof fetch> {
+  const fetchMock = vi.fn<typeof fetch>()
+  for (const response of responses) fetchMock.mockResolvedValueOnce(response)
+  fetchMock.mockImplementation((input, init) => {
+    throw new Error(`unexpected fetch: ${init?.method ?? 'GET'} ${String(input)}`)
+  })
+  vi.stubGlobal('fetch', fetchMock)
+  return fetchMock
+}
+
+// request returns the method, path and headers of the fetch mock's nth call.
+export function request(fetchMock: Mock<typeof fetch>, n: number) {
+  const call = fetchMock.mock.calls[n]
+  if (call === undefined) throw new Error(`fetch was called ${fetchMock.mock.calls.length} times, not ${n + 1}`)
+  const [input, init] = call
+  return {
+    path: String(input),
+    method: init?.method,
+    credentials: init?.credentials,
+    headers: new Headers(init?.headers),
+    body: init?.body,
+  }
+}
+
+// fakeLocation stands in for window.location, recording navigations.
+export function fakeLocation(pathname = '/', search = ''): ApiLocation & { assign: Mock<(url: string | URL) => void> } {
+  return { pathname, search, assign: vi.fn<(url: string | URL) => void>() }
+}