[Bug] Markdown CJK wrap duplicates glyph at specific widths

[stephanoskomnenos]

Summary

Rendering Markdown with CJK content can duplicate a fullwidth glyph at specific terminal widths where the line wraps.

Repro

Repo: https://github.com/stephanoskomnenos/opentui-md-wrap-demo

Commands:

• scripts/capture.sh --tmux-columns 38 --out-png ./tmp/demo-38.png
• scripts/capture.sh --tmux-columns 39 --out-png ./tmp/demo-39.png
• scripts/capture.sh --tmux-columns 40 --out-png ./tmp/demo-40.png

Expected

No duplicated glyph on wrap.

Actual

At width 39, the wrap boundary duplicates a CJK glyph ("确" appears both at end of line and again on next line).

Screenshots (38/39/40)

ANSI/HTML/PNG are included in the repo under tmp/.

Environment (devcontainer)

• @opentui/core: 0.1.87
• @opentui/react: 0.1.87
• Bun runtime (Linux)
• Rendering via <markdown> component

[kommander]

@simonklee didn't we just fix that recently, is that a regression?

[simonklee]

@simonklee didn't we just fix that recently, is that a regression?

Not that i remember. i have a branch where i've fixed it — but that is massive (all my scan layout wrapping things) main...simonklee:scan-wrap

I'll have a look at this.