fix(subagent): close stacked catalog integration gaps

packages/support/acp-snapshot/src/harness.ts

@@ -66,6 +66,7 @@ export type InputStep =
     text: string
     waitForFile?: { path: string; timeoutMs?: number }
   }
+  | { op: 'waitForFile'; path: string; timeoutMs?: number }
   | { op: 'waitForTurnStart'; minimumTurn?: number; timeoutMs?: number }
   | { op: 'waitForTurnEnd'; timeoutMs?: number }
   | { op: 'waitForTitleAfterTurnEnd'; timeoutMs?: number }
@@ -436,6 +437,9 @@ async function runStep(
       await promptDone
       return
     }
+    case 'waitForFile':
+      await waitForWorkspaceFile(cwd, step.path, step.timeoutMs)
+      return
     case 'waitForTurnEnd': {
       const sessionId = getSessionId()
       if (sessionId === undefined) throw new Error('snapshot-harness: waitForTurnEnd before newSession')

packages/support/acp-snapshot/tests/harness.spec.ts

@@ -865,6 +865,19 @@ describe('runScenario', () => {
     expect(result.sessionId).toBeDefined()
   })
 
+  it('waitForFile holds the next input step behind cwd-relative readiness', { timeout: 20_000 }, async () => {
+    const { dir, fixtureFile } = await scenario({})
+    const workspaceDir = join(dir, 'workspace')
+    const { mkdir } = await import('node:fs/promises')
+    await mkdir(workspaceDir, { recursive: true })
+    await writeFile(join(workspaceDir, 'ready'), '')
+    const result = await runScenario(
+      { steps: [...boot, { op: 'waitForFile', path: 'ready' }, { op: 'cancel' }] },
+      { agent: AGENT, mode: 'replay', fixtureFile, workspaceDir },
+    )
+    expect(result.sessionId).toBeDefined()
+  })
+
   it.each([
     [{ op: 'prompt', text: 'x' }, /prompt before newSession/],
     [{ op: 'promptAndWaitForAgentMessage', text: 'x', waitForText: 'later' }, /promptAndWaitForAgentMessage before newSession/],