Permission mode indicator icons garbled on macOS 12 (Monterey)

Description

The permission mode indicator at the bottom of the Claude Code terminal UI displays garbled/mojibake characters on macOS 12 (Monterey). The icons before "accept edits on" and "bypass permissions on" render as broken squares/boxes.

Environment

• OS: macOS 12.6.x (Monterey)
• Claude Code: latest (CLI)
• Terminal: macOS default Terminal / iTerm2

Steps to Reproduce

1. Run Claude Code on macOS 12 (Monterey)
2. Look at the bottom bar showing the permission mode (e.g., "accept edits on" or "bypass permissions on")
3. The icon before the text renders as garbled characters

Expected Behavior

The icons should render correctly, or fall back to ASCII/basic Unicode characters that are supported on older macOS versions.

Suggested Fix

• Detect the OS version and use ASCII fallback characters on older macOS versions
• Or use characters from widely-supported Unicode blocks (e.g., Geometric Shapes, Basic Latin)