Ctrl+B Keybinding Conflict on Linux (Ubuntu)

Issue Description

The Ctrl+B hotkey for running background commands in Claude Code conflicts with the default linux terminal keybinding for moving the cursor backward by one character.

Closely related with the same problem on Macos: https://github.com/anthropics/claude-code/issues/5376

Problem Details

Claude Code Version: 1.0.71+ (feature introduced in 1.0.71)
Platform: Linux (tested on Ubuntu 24.04)
Conflicting Keybinding: Ctrl+B is a standard Unix terminal keybinding for backward cursor movement
Expected Feature: Run Bash commands in background while Claude continues working

Impact

Linux users cannot use the background command feature as the system intercepts Ctrl+B for cursor navigation, preventing Claude Code from receiving the keystroke.

Reproduction Steps

Open Claude Code on Linux
Try to use Ctrl+B to run a command in background
Observe that cursor moves backward instead of triggering background execution

Suggested Solutions

Add configurable keybindings: Allow users to customize the background command hotkey through settings.json
Use different default on Linux: Detect Linux and use an alternative default keybinding (e.g. Ctrl+Shift+B)
Multiple keybinding options: Support multiple keybindings for the same action

Workaround

Currently, there is no workaround. Even if user disables the readline keybinding in shell, in Claude Code the behaviour is not altered (while in bash directly ctrl+b no longer trigger pointer move backward, in Claude Code it still does).