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/components/memory/memoryFileSelectorPaths.ts

@@ -0,0 +1,34 @@
+import { basename, join } from 'path'
+
+import type { MemoryFileInfo } from '../../utils/claudemd.js'
+import {
+  findProjectInstructionFilePathInAncestors,
+  isProjectInstructionFileName,
+  PRIMARY_PROJECT_INSTRUCTION_FILE,
+} from '../../utils/projectInstructions.js'
+
+function isLoadedProjectInstructionFile(file: MemoryFileInfo): boolean {
+  return (
+    file.type === 'Project' &&
+    file.parent === undefined &&
+    isProjectInstructionFileName(basename(file.path))
+  )
+}
+
+export function getProjectMemoryPathForSelector(
+  existingMemoryFiles: MemoryFileInfo[],
+  cwd: string,
+): string {
+  const loadedProjectInstructionPaths = new Set(
+    existingMemoryFiles
+      .filter(isLoadedProjectInstructionFile)
+      .map(file => file.path),
+  )
+
+  return (
+    findProjectInstructionFilePathInAncestors(
+      cwd,
+      path => loadedProjectInstructionPaths.has(path),
+    ) ?? join(cwd, PRIMARY_PROJECT_INSTRUCTION_FILE)
+  )
+}