Prefer AGENTS.md over CLAUDE.md for project instructions (#439)

* Prefer AGENTS.md over CLAUDE.md for project instructions

* fix: preserve CLAUDE.md fallback behavior

* fix: isolate onboarding tests and preserve legacy init

* fix: restore full fsOperations exports in test mock and align compact cwd

* Fix onboarding test isolation and init migration guidance

* Tighten init prompt coverage and onboarding copy

* Handle nested project instruction paths consistently

* Fix NEW_INIT feature gate for Bun build

---------

Co-authored-by: 赵小落 <zhaoxiaoluo@zhaoxiaoluodeMac-mini.local>
Co-authored-by: zhaomo01 <zhaomo01@baidu.com>

src/projectOnboardingState.test.ts

@@ -0,0 +1,62 @@
+import { afterEach, describe, expect, test } from 'bun:test'
+import { mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+
+import {
+  getSteps,
+  isProjectOnboardingComplete,
+} from './projectOnboardingSteps.js'
+import { runWithCwdOverride } from './utils/cwd.js'
+
+let tempDir: string | undefined
+
+afterEach(async () => {
+  if (tempDir) {
+    await rm(tempDir, { recursive: true, force: true })
+    tempDir = undefined
+  }
+})
+
+describe('project onboarding completion', () => {
+  test('is incomplete when neither AGENTS.md nor CLAUDE.md exists', async () => {
+    tempDir = await mkdtemp(join(tmpdir(), 'project-onboarding-'))
+
+    await runWithCwdOverride(tempDir, async () => {
+      expect(isProjectOnboardingComplete()).toBe(false)
+      expect(getSteps()[1]?.text).toContain('/init')
+      expect(getSteps()[1]?.text).toContain('AGENTS.md')
+      expect(getSteps()[1]?.text).toContain('CLAUDE.md')
+    })
+  })
+
+  test('is complete when only CLAUDE.md exists', async () => {
+    tempDir = await mkdtemp(join(tmpdir(), 'project-onboarding-'))
+    await writeFile(join(tempDir, 'CLAUDE.md'), '# CLAUDE.md\n')
+
+    await runWithCwdOverride(tempDir, async () => {
+      expect(isProjectOnboardingComplete()).toBe(true)
+    })
+  })
+
+  test('is complete when only AGENTS.md exists', async () => {
+    tempDir = await mkdtemp(join(tmpdir(), 'project-onboarding-'))
+    await writeFile(join(tempDir, 'AGENTS.md'), '# AGENTS.md\n')
+
+    await runWithCwdOverride(tempDir, async () => {
+      expect(isProjectOnboardingComplete()).toBe(true)
+    })
+  })
+
+  test('is complete from a nested cwd when repo instructions exist in an ancestor directory', async () => {
+    tempDir = await mkdtemp(join(tmpdir(), 'project-onboarding-'))
+    const nestedDir = join(tempDir, 'packages', 'app')
+    await writeFile(join(tempDir, 'AGENTS.md'), '# AGENTS.md\n')
+    await mkdir(nestedDir, { recursive: true })
+    await writeFile(join(nestedDir, 'index.ts'), 'export {}\n')
+
+    await runWithCwdOverride(nestedDir, async () => {
+      expect(isProjectOnboardingComplete()).toBe(true)
+    })
+  })
+})