Codex desktop terminal rendering artifact duplicates leading characters (git -> ggit)

What version of the Codex App are you using (From “About Codex” dialog)?

Version 26.406.31014 (1395)

What subscription do you have?

Enterprise

What platform is your computer?

Darwin 24.6.0 arm64 arm

What issue are you seeing?

In the Codex desktop terminal, the command line sometimes renders extra/stale leading characters while typing/editing commands (for example git appears as ggit, or gh remains visually stuck). Commands execute correctly, so this appears to be a rendering/redraw mismatch. Does not reproduce in iTerm2 or VSCode with the same ~/.zshrc.

<img width="231" height="211" alt="Image" src="https://github.com/user-attachments/assets/36234a14-84a1-47fa-a2e1-94ca957c578b" />

What steps can reproduce the bug?

Reproduction
Open Codex desktop terminal.
Start zsh with standard ~/.zshrc (not zsh -f).
Type/edit short commands like git, gh, cat.
Backspace/clear/retype.
Observe stale/duplicated leading chars (ggit, ghnano, excat).

What is the expected behavior?

Rendered input should always match actual shell buffer.

Additional information

Shell: zsh (normal config reproduces; zsh -f changes behavior)
Prompt: starship
Plugins: zsh-autosuggestions, zsh-syntax-highlighting
iTerm integration script present (~/.iterm2_shell_integration.zsh) and tested with Codex-only disable
CODEX_HOME-gated attempts (disabled autosuggestions/highlighting in Codex) did not fully resolve
Not reproducible in iTerm2 or VSCode terminal with same .zshrc

eval "$(starship init zsh)"
if [[ -n "${CODEX_HOME}" ]]; then
  :
else
  source /opt/homebrew/share/zsh-autosuggestions/zsh-autosuggestions.zsh
  source /opt/homebrew/share/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh
fi

Possibly related to #16687, #16170, #16575, #16306, but behavior differs: desktop renderer mismatch with correct command execution.