[BUG] Theme should not be changed on `Esc`

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.43
• Operating System: linux, windows-terminal, v1.0.41 (win10 wsl ubuntu 24)
• Terminal: modern windows terminal

Bug Description

Lets say your current theme is Dark.
You can move (select to preview) to another theme to see how it looks.
Now you can cancel theme changing on Esc.
And the config theme's menu immediately says that discarded theme is now your current theme.

Steps to Reproduce

See Bug Description.

Expected Behavior

The current theme should not be changed on Esc in theme preview.

Actual Behavior

See Bug Description.

Additional Context

<!-- Add any other context about the problem here, such as screenshots, logs, etc. -->