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/commands/initMode.ts

@@ -0,0 +1,13 @@
+import { feature } from 'bun:bundle'
+import { isEnvTruthy } from '../utils/envUtils.js'
+
+export function isNewInitEnabled(): boolean {
+  if (feature('NEW_INIT')) {
+    return (
+      process.env.USER_TYPE === 'ant' ||
+      isEnvTruthy(process.env.CLAUDE_CODE_NEW_INIT)
+    )
+  }
+
+  return false
+}