[BUG] TUI leaves local terminal in mouse-tracking mode after ungraceful SSH disconnect

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When running Claude Code in a screen session over SSH, an ungraceful disconnect leaves the local terminal emulator in mouse-tracking mode, causing mouse movement to generate escape sequence artifacts:

Local terminal is left in mouse-tracking mode. Example output:

C!HC$HC'HC*HC+HC,HC-H -H#-Ha-Ha-Hc-HC.HC/HC0HC1IC2IC4JC6JC8KC:LC=MC@NCANCCOCEPCFPCGQCHQCIRCJRCKSCLSCLTCLUCKUCJUCIUCHUCFUCEVCDVCCWCBWCAXC@XC?YC>YC=YC=ZC<ZC<[C=[C>[C>\C?\C@\C@]C@^ @^@?^@>^@=^@<^@;^@:^@9^@8^@8]@7]@6]@5]@4]#4]C3]S2]S2\S1\S0\00\P1\P2\P3]P4]P5]#5] 5]@4]```

I have also opened an issue with ghostty: https://github.com/ghostty-org/ghostty/discussions/12700

### What Should Happen?

The terminal should reset mouse tracking mode.

### Error Messages/Logs

```shell

Steps to Reproduce

Steps to Reproduce:

1. SSH to remote machine
2. Start or attach to screen session
3. Run claude (enters TUI mode)
4. Force ungraceful SSH disconnect using ~. (SSH escape sequence)
5. Mouse movement in local terminal produces artifacts

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.141

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

Other

Additional Information

Local OS: macOS 26.4.1
Local terminal: Ghostty 1.3.1 (also reproduces in iTerm2)
Remote OS: Linux 5.10 (x86_64)
Screen version: 4.01.00devel (GNU) 2-May-06