Mac: 'alt+t to toggle thinking' shortcut doesn't work and should show platform-specific keybinding

Description

On macOS, Claude Code displays "alt+t to toggle thinking" hint, but this shortcut doesn't work because:

1. macOS doesn't have an "Alt" key - it has "Option" key
2. Even when pressing Option+T, it doesn't toggle thinking mode (Option key combinations in terminal often input special characters instead)

Expected Behavior

• On macOS, show a working shortcut (e.g., "⌥T" or provide an alternative like "Cmd+T")
• Or detect the platform and show platform-specific keybindings
• Or provide a shortcut that actually works on macOS terminals

Current Workaround

Users must use /config command to toggle thinking mode, which is not discoverable from the displayed hint.

Environment

• OS: macOS
• Terminal: Various (Terminal.app, iTerm2, etc.)