Single character input not displayed when submitting with Ctrl+M

Bug Description

When submitting a single character input using Ctrl+M, the user's input text is not displayed in the chat history. The message is sent and Claude responds normally, but the user's input line is invisible.

Steps to Reproduce

1. Open Claude Code in terminal
2. Type a single character (e.g., v, k, 1)
3. Press Ctrl+M to submit
4. The user's input is not shown in the chat history

Expected Behavior

The single character input should be displayed in the chat history, just like when pressing the Enter key.

Actual Behavior

• Single character + Ctrl+M → input text not displayed
• Single character + Enter → input text displayed correctly
• 2+ characters + Ctrl+M → input text displayed correctly

Environment

• Claude Code version: 2.1.74
• OS: macOS 26.3.1 (Apple M2)
• Terminal: Ghostty + Zellij (v0.43.1)
• Shell: zsh
• support_kitty_keyboard_protocol false in Zellij config

Notes

Ctrl+M and Enter should send the same key code (ASCII 13 / carriage return), so this discrepancy is unexpected. The issue only occurs with single character inputs.