[Bug] ctrl+c does not close /usage view

Bug Report

### Current Behavior
When viewing /usage, pressing ctrl+c does not close/dismiss the view. Only escape works.

### Expected Behavior
ctrl+c should dismiss the /usage view, consistent with how it works in other overlay views like the transcript (transcript:exit supports both ctrl+c and escape).

### Steps to Reproduce

1. Open Claude Code
2. Type /usage and press Enter
3. Press ctrl+c
4. Observe that the view does not close

### Environment

• OS: macOS (Darwin)
• Terminal: iTerm.app
• Claude Code version: 2.1.52
• Feedback ID: 772d2e62-97fa-4386-80b7-c0c3fb19bab7