tui: clipboard-pasted text lands with multi-second delay in question dialog answer field

Summary

When dictating into a question dialog's free-text field (the "type your own answer" option of the multiple-choice question prompt), text inserted via clipboard paste takes several seconds to appear. The same dictation method into the main message composer lands instantly, and manual keyboard typing into the question dialog field is fully responsive — so the delay appears specific to how the question dialog's text input handles pasted input.

Environment

• opencode version: 0.0.0-beta-18138
• OS: macOS (Darwin 25.6.0, arm64)
• Terminal: cmux on the client Mac, connected over SSH to the host running opencode inside a tmux session (TERM=xterm-256color, COLORTERM=truecolor)
• Shell: /bin/zsh
• Install/channel: beta
• Active plugins: none configured

Reproduction

1. Run the opencode TUI (v0.0.0-beta-18138) in tmux over SSH.
2. Use Handy (voice-to-text) configured with the clipboard paste insertion method — it copies the transcript to the clipboard and simulates a paste keystroke.
3. Trigger an agent question dialog (e.g. a tool asking a multiple-choice question) and select the free-text/custom answer option.
4. Dictate a response so Handy pastes it into the custom-answer field.
5. Compare with dictating into the main message composer.

Expected Behavior

Pasted/dictated text should appear in the question dialog's custom-answer field as promptly as it does in the main message composer.

Actual Behavior

The text appears only after a noticeable fixed lag of roughly a few seconds, regardless of dictated length. Observed behavior:

• Main composer + same Handy clipboard-paste method: instant.
• Question dialog custom-answer field + manual keyboard typing: instant/responsive.
• Question dialog custom-answer field + Handy clipboard-paste: consistent multi-second delay before the text shows up.

No missing or duplicated characters were observed — the text arrives complete once the delay passes. Reproduces consistently.

Additional Context

Since manual typing is fast and the identical paste path is instant in the main composer, the culprit seems to be in the question dialog's input handling of pasted text (e.g. how it consumes bracketed-paste input from the terminal vs. the main editor). Happy to help narrow it down further if useful.