Describe the bug

After exiting Claude Code, the terminal remains in an enhanced keyboard input mode (modifyOtherKeys / kitty keyboard protocol). Ctrl-C, Ctrl-D, and other control key combinations stop working — they produce escape sequences like 9;5u instead of sending the expected signals (SIGINT, EOF, etc.).

To reproduce

1. Open Ghostty inside tmux
2. Run claude
3. Use Claude Code normally
4. Exit Claude Code (Escape, or /exit)
5. Press Ctrl-C or Ctrl-D in the shell

Expected: Ctrl-C sends SIGINT, Ctrl-D sends EOF — normal shell behavior.
Actual: Ctrl-C produces 9;5u, Ctrl-D produces 0;5u, etc. Terminal is stuck in enhanced key mode.

Workaround

Running reset or printf '\e[>4;0m\e[>0m' restores normal terminal behavior.

Environment

• Claude Code version: latest (issue started in last 1-2 releases)
• OS: macOS (Darwin 24.6.0)
• Terminal: Ghostty
• Multiplexer: tmux
• Shell: zsh

Additional context

• The root cause is that Claude Code enables modifyOtherKeys or the kitty keyboard protocol for enhanced input, but does not properly restore terminal state on exit.
• Terminals that support these protocols (Ghostty, Kitty, and other modern emulators) are affected. Older terminals that ignore the escape sequences are not.
• Related issue in another project with the same symptoms: [Bug]: Ctrl-C (or any ctrl+key) does not work after invoking atuin with Ctrl-R atuinsh/atuin#2256