[BUG] @ symbol not working with Danish keyboard layout (macOS)

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?

Description

The @ symbol cannot be typed in Claude Code when using a Danish keyboard layout on macOS. Attempting to type @ using the standard Danish keyboard shortcut (Option+2)
produces an apostrophe character (') instead.

## Environment

• OS: macOS (Darwin 24.6.0)
• Keyboard Layout: Danish (DK)
• Other layouts enabled: Swedish-Pro, Russian-Phonetic
• System Locale: en_DK
• Claude Code Version: v2.0.28

## Expected Behavior
Typing Option+2 should produce @ symbol for @-mentioning files in Claude Code

## Actual Behavior
Typing Option+2 produces apostrophe (') character instead

## Impact

• Cannot use @-mention feature for files
• Significantly impacts UX for non-US keyboard users

What Should Happen?

## Expected Behavior
Typing Option+2 should produce @ symbol for @-mentioning files in Claude Code

Error Messages/Logs

Steps to Reproduce

## Steps to Reproduce

1. Set keyboard layout to Danish
2. Open Claude Code
3. Try to type @ symbol using Option+2 (standard Danish keyboard mapping)
4. Observe that apostrophe (') appears instead

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

v2.0.28

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

## Additional Notes
The @ symbol works correctly in other applications (browser, text editors) with the same keyboard layout, suggesting this is specific to Claude Code's input handling.