Multiple choice prompts don't line break correctly in narrow terminal panes

Description

When using Claude Code in a tmux split pane that falls below a certain width threshold, the multiple choice prompt text doesn't line break correctly. The text overflows/wraps incorrectly, making it difficult to read and respond to prompts.

Steps to Reproduce

1. Open Claude Code in a tmux session
2. Split the pane horizontally or vertically so the Claude pane is narrower than ~80 columns
3. Trigger a multiple choice prompt (e.g., via AskUserQuestion or any built-in prompt)
4. Observe that the prompt text doesn't wrap correctly to the pane width

Expected Behavior

Prompt text should wrap correctly to the terminal/pane width, respecting COLUMNS or responding to SIGWINCH signals.

Actual Behavior

Text overflows without proper line breaks when pane width drops below a certain threshold (~80 columns).

Environment

• macOS (Darwin 25.2.0)
• tmux with default-terminal "tmux-256color"
• TERM=xterm-256color, COLORTERM=truecolor
• Pane width during reproduction: ~60 columns

Possible Cause

The terminal UI library (Ink?) may not be correctly detecting or responding to narrow terminal widths, or may have a hardcoded minimum width assumption.

Workaround

Zoom the pane (Ctrl-b z / Ctrl-a z) before answering prompts, or keep panes at 80+ columns.