Bug Description

In the Hermes TUI/CLI input box, typing Chinese characters (and likely other East Asian wide characters such as Japanese/Korean) renders incorrectly.

The input area appears to calculate layout/cursor/line width as if the characters were single-width, which causes the input box to become visually wrong when entering CJK text.

This looks related to a previous Hermes TUI/input-box rendering bug around line layout / segmentation / width calculation that was fixed for normal English/ASCII input, but the fix does not appear to fully handle East Asian wide characters.

Expected Behavior

When typing Chinese / Japanese / Korean characters in the TUI input box:

• cursor position should stay aligned with the actual text
• wrapped lines should break at the correct visible columns
• the input box border/layout should remain visually correct
• editing should work the same way as with ASCII text

Actual Behavior

When typing Chinese characters in the TUI input box:

• the input box becomes visually wrong / misaligned
• cursor and/or wrapping appears incorrect
• the issue seems specific to East Asian wide characters rather than English text

Steps to Reproduce

1. Start Hermes in the TUI / CLI interface
2. Focus the normal input box
3. Type Chinese text (for example: 你好你好你好你好 or a longer Chinese sentence)
4. Continue typing until the line should wrap or the cursor moves across the input region
5. Observe that the input box layout/cursor/rendering is incorrect

Example Repro Text

You can reproduce with something like:

你好，这是一个用于测试 Hermes TUI 输入框宽度计算的中文句子。

Or shorter repeated wide characters:

你好你好你好你好你好你好

Expected Root Cause Area

Likely related to terminal/TUI width calculation for wide Unicode characters:

• East Asian width / fullwidth character handling
• wcwidth / wcswidth behavior
• prompt_toolkit integration for cursor positioning / wrapping
• any custom line segmentation logic added in earlier TUI fixes

Why this may be related to an earlier bug

There was previously a Hermes TUI/input-box rendering bug involving line layout/segmentation that appears to have been fixed for English characters.

This report is specifically that the problem still exists for CJK/East Asian characters, suggesting the previous fix may have assumed single-column characters.

Environment

• Product: Hermes CLI / TUI
• Input language: Chinese (likely affects other East Asian scripts too)
• Character class likely involved: wide Unicode / East Asian width characters

Notes

This issue is about the local TUI input box rendering/editing experience, not model output.

It would be ideal to verify against:

• Chinese input
• Japanese kana/kanji
• Korean Hangul
• mixed ASCII + CJK input
• line wrapping and backspacing near wrap boundaries