[BUG] @ file search is case-sensitive, making lowercase input fail to find matching files

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When using the @ file mention to reference project files, the search is case-sensitive. If a filename uses mixed case (e.g. UserProfile.tsx), typing it in all lowercase returns no results, forcing users to remember exact casing to find files.

What Should Happen?

The @ file search should match files case-insensitively, similar to how most modern editors (VS Code, JetBrains, Zed) handle fuzzy file search. Typing @userprofile should surface UserProfile.tsx.

Error Messages/Logs

Steps to Reproduce

1. Open a project containing a file named e.g. "UserProfile.tsx"
2. In Claude Code, type: @userprofile
3. Observe: no matching file appears in the dropdown
4. Type: @UserProfile
5. Observe: file is found correctly

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.132 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_