File indexing broken for Next.js app directories with dynamic routes (brackets in folder names)

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other:
• Claude CLI version: <!-- run claude --version in terminal -->
• Operating System: macOS 14.6 (Darwin 23.6.0)
• Terminal: Terminal App

Bug Description

The @ mention file picker completely fails to index any files within directories that contain Next.js dynamic route folders (folders with brackets like [id], [username]). This was working perfectly an hour ago but broke after creating a new Claude Code instance. The issue only affects directories containing bracketed subdirectories - other directories work fine.

Steps to Reproduce

1. Open a Next.js project with app router structure
2. Have directories like src/app/users/[id]/page.tsx or src/app/blog/[slug]/page.tsx
3. Try to use @ mention to reference any file within src/app or src/components
4. Notice that NO files from these directories appear in the picker
5. Try @ mentioning files from src/utils or src/services (no bracketed subdirs) - these work fine

Expected Behavior

All files in the project should be indexed and available via @ mention, including those in directories containing Next.js dynamic routes with brackets.

Actual Behavior

• Files in src/app and src/components (which contain dynamic route folders) are completely missing from @ mention picker
• Files in src/utils and src/services (no dynamic routes) work perfectly
• This is a regression - it worked in the previous Claude Code instance from an hour ago

Additional Context

• Project structure uses Next.js 15 with app router
• Running find src/app -name "*.tsx" shows 50+ files that should be indexed but aren't
• Cleared all caches with rm -rf ~/.cache/claude* - didn't help
• The pattern is clear: any directory tree containing folders with brackets [param] fails to index
• 557 total files in project (excluding node_modules, .next, etc)
• File watcher limits are fine (kern.maxfilesperproc: 2200000)