Line numbers appear garbled in code diff display within VSCode chat panel

Description

Line numbers appear garbled/corrupted in the chat panel when Claude Code displays code modifications or diffs inside the VSCode extension.

Steps to Reproduce

1. Open a project in VSCode with the Claude Code extension installed
2. Ask Claude to modify code in a file
3. Observe the code modification section displayed in the chat panel
4. The line numbers shown alongside the code appear as garbled/corrupted characters

Expected Behavior

Line numbers should display correctly as readable digits (e.g., 1, 2, 3...).

Actual Behavior

Line numbers appear as garbled or corrupted characters in the chat panel's code display area.

Environment

• Platform: Windows 11
• Editor: VSCode with Claude Code extension
• The issue appears in the Webview-based chat panel

Notes

This appears to be a rendering issue specific to the Webview component used by the extension, as VSCode editor font settings do not apply to the chat panel. Adding fonts in VSCode settings does not resolve the issue.