Inline-rich mode + CJK fragment cause overflow

[codehz]

repro: https://codehz.github.io/pretext-bug-diag/ (source: github.com/codehz/pretext-bug-diag)

It only happens when using chinese + inline rich mode, it appears to be related to Chinese typesetting rules.

Although the reproduction code was generated by AI, I believe it accurately reflects the bug that actually occurred(I have checked the code).