fix(tui): drain Kitty key release events before exit to prevent SSH leak

Adds Terminal.prepareForExit() to disable Kitty protocol and wait for
in-flight release events before fully stopping. This prevents escape
sequences from leaking to the parent shell over slow SSH connections.

Fixes #1204

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed Kitty key release events leaking to parent shell over slow SSH connections ([#1204](https://github.com/badlogic/pi-mono/issues/1204))
+
 ## [0.51.1] - 2026-02-02
 
 ### New Features