Create input simulation test harness for keyboard injection methods

[Coldaine]

Issue Description

Create a dedicated test harness to validate keyboard simulation methods (ydotool, enigo, kdotool) in controlled environments.

Current State

• Input simulation methods lack comprehensive integration testing
• No way to validate that simulated keystrokes actually work
• Cannot verify keyboard injection succeeds across different environments
• Tests for ydotool, enigo, and kdotool are disabled

Requirements

1. Create a text capture application that receives simulated keystrokes
2. Implement validation system to verify injected text matches expected
3. Test different keyboard layouts and special characters
4. Verify clipboard-based injection followed by paste commands (ydotool)
5. Test timing and race condition scenarios
6. Support for both X11 and Wayland contexts where applicable

Benefits

• Verify actual keyboard input functionality
• Catch keyboard simulation regressions
• Ensure special characters and timing work correctly
• Validate paste-based injection workflows
• Cross-platform compatibility validation

[google-labs-jules]

Jules is on it. When finished, you will see another comment and be able to review a PR.

[google-labs-jules]

Ready for a review! A PR has been created.