fix(build): add 'Keep going' button to resume stalled generation (#1038)

__tests__/components/build/ArtifactFrame-keep-going.test.tsx

@@ -0,0 +1,132 @@
+// @vitest-environment jsdom
+import { describe, it, expect, vi, beforeAll, afterEach } from 'vitest'
+import React from 'react'
+import { createRoot, type Root } from 'react-dom/client'
+import { act } from 'react'
+
+beforeAll(() => {
+  ;(globalThis as any).React = React
+  ;(globalThis as any).IS_REACT_ACT_ENVIRONMENT = true
+})
+
+/**
+ * #1038: once state.auto becomes false (via "Take the wheel", or via resuming
+ * an in-progress build — START_BUILD's resume path per #1033 deliberately
+ * leaves auto:false), there was NO UI affordance anywhere that dispatched
+ * KEEP_GOING (auto: true) — the reducer case existed but had zero callers.
+ * Autoplay's own gate (useAutoplay.ts:82-83) means a paused-but-unfinished
+ * build silently stopped generating forever.
+ *
+ * This test asserts ArtifactFrame renders a "Keep going" button, wired to
+ * dispatch({ type: 'KEEP_GOING' }), exactly when the build is paused
+ * (!state.auto) AND the active track still has undone/non-errored views
+ * remaining — mirroring useAutoplay.ts's own trackViews(state.track) +
+ * state.done/state.genError "next" lookup, not a reinvented check.
+ */
+
+let mockState: any
+const dispatchMock = vi.fn()
+const goViewMock = vi.fn()
+vi.mock('@/contexts/build-context', () => ({
+  useBuild: () => ({
+    state: mockState,
+    views: ['thesis', 'wedge', 'businessModel', 'positioning', 'landing', 'plan30'],
+    goView: goViewMock,
+    dispatch: dispatchMock,
+  }),
+}))
+
+import { ArtifactFrame } from '@/components/build/ArtifactFrame'
+
+let host: HTMLElement
+let root: Root
+
+function render(view = 'businessModel') {
+  host = document.createElement('div')
+  document.body.appendChild(host)
+  root = createRoot(host)
+  act(() => {
+    root.render(
+      React.createElement(ArtifactFrame, { title: 'Business Model', status: 'done', view }),
+    )
+  })
+}
+
+function baseState(overrides: Partial<any> = {}) {
+  return {
+    companyName: 'Acme',
+    idea: 'A coffee subscription platform',
+    track: 'company',
+    auto: false,
+    paused: false,
+    generated: {},
+    done: { thesis: true, wedge: true },
+    genError: {},
+    appChatId: 'acme-co',
+    sawPreview: false,
+    conflictResolved: false,
+    ...overrides,
+  }
+}
+
+function keepGoingButton() {
+  return Array.from(host.querySelectorAll('button')).find((b) => /keep going/i.test(b.textContent || ''))
+}
+
+afterEach(() => {
+  act(() => { root?.unmount() })
+  host?.remove()
+  vi.clearAllMocks()
+  vi.unstubAllGlobals()
+})
+
+describe('ArtifactFrame "Keep going" resume affordance (#1038)', () => {
+  it('renders a Keep going button when paused (auto:false) with unfinished track views', () => {
+    mockState = baseState() // auto:false, businessModel/positioning/landing/plan30 all undone
+    render('businessModel')
+
+    const btn = keepGoingButton()
+    expect(btn).toBeTruthy()
+  })
+
+  it('dispatches KEEP_GOING when clicked, restoring auto:true via the reducer', () => {
+    mockState = baseState()
+    render('businessModel')
+
+    const btn = keepGoingButton()!
+    act(() => { btn.dispatchEvent(new MouseEvent('click', { bubbles: true })) })
+
+    expect(dispatchMock).toHaveBeenCalledWith({ type: 'KEEP_GOING' })
+  })
+
+  it('does NOT render Keep going when auto is already true', () => {
+    mockState = baseState({ auto: true })
+    render('businessModel')
+
+    expect(keepGoingButton()).toBeFalsy()
+  })
+
+  it('does NOT render Keep going when the track is actually finished (no undone/non-errored views remain)', () => {
+    mockState = baseState({
+      auto: false,
+      done: {
+        design: true, thesis: true, wedge: true, businessModel: true,
+        positioning: true, landing: true, plan30: true,
+      },
+    })
+    render('plan30')
+
+    expect(keepGoingButton()).toBeFalsy()
+  })
+
+  it('still renders the manual ‹ Back / Next › pager alongside Keep going when paused', () => {
+    mockState = baseState()
+    render('businessModel')
+
+    const backBtn = Array.from(host.querySelectorAll('button')).find((b) => /back/i.test(b.textContent || ''))
+    const nextBtn = Array.from(host.querySelectorAll('button')).find((b) => /next/i.test(b.textContent || ''))
+    expect(backBtn).toBeTruthy()
+    expect(nextBtn).toBeTruthy()
+    expect(keepGoingButton()).toBeTruthy()
+  })
+})

components/build/ArtifactFrame.tsx

@@ -18,7 +18,7 @@
  */
 
 import { useBuild } from '@/contexts/build-context'
-import { SHARED_LATE_VIEWS } from '@/lib/build/state'
+import { SHARED_LATE_VIEWS, trackViews } from '@/lib/build/state'
 import { collectPrior, serializeArtifact, applyEdit } from '@/lib/build/artifact-edit'
 import { CompanyNameEdit } from '@/components/build/CompanyNameEdit'
 import { useState, type ReactNode } from 'react'
@@ -62,6 +62,19 @@ export function ArtifactFrame({
   const isLate = isSharedLateView(view)
   const companyLabel = state.companyName || 'company'
 
+  // #1038: "Take the wheel" (and resuming an in-progress build, which per
+  // #1033's START_BUILD comment deliberately leaves auto:false) sets
+  // state.auto to false, which is the ONLY gate useAutoplay.ts checks before
+  // it will fetch another artifact. KEEP_GOING (auto: true) has existed in
+  // the reducer the whole time but had no caller anywhere in the component
+  // tree — so once paused, a build could never resume on its own. Surface a
+  // "Keep going" affordance whenever paused AND the active track still has
+  // real work left, using the exact same "next undone, non-errored view"
+  // lookup useAutoplay.ts itself uses to decide whether a track is complete,
+  // so this never appears once the track has actually finished.
+  const hasUnfinishedWork = trackViews(state.track).some((v) => !state.done?.[v] && !state.genError?.[v])
+  const canKeepGoing = !isLate && !state.auto && hasUnfinishedWork
+
   // ── Per-artifact review actions (GR-16 #329) ──────────────────────────────
   // Shown on every artifact that has GENERATED content (prose views after
   // GEN_DONE). Build views (swarm/infra/preview) and late shared views have no
@@ -259,6 +272,16 @@ export function ArtifactFrame({
       ) : !state.auto ? (
         <div className="m-artifact-nav">
           <button className="btn-ghost" disabled={!prev} onClick={() => prev && goView(prev as never)}>‹ Back</button>
+          {/* #1038: restores the dead KEEP_GOING path — the only way back to
+              autoplay once paused (via "Take the wheel" or a resumed build)
+              was previously nonexistent. Hidden once the track has actually
+              finished (hasUnfinishedWork is false), since there's nothing
+              left for autoplay to resume. */}
+          {canKeepGoing && (
+            <button className="btn-secondary" onClick={() => dispatch({ type: 'KEEP_GOING' })}>
+              Keep going →
+            </button>
+          )}
           {/* On the LAST artifact (e.g. preview) there is no next artifact, so the
               pager 'Next' used to be a disabled dead-end — users clicked it and
               nothing happened. Instead, advance to the pricing/pay-gate (the real