Improve permission and viewing flows

[codeugar]

What changed

• checks Input Monitoring immediately when Start is pressed, before starting the countdown
• hides CleanMyScreen after Pet / Kid or Selective becomes active so the previous video or app is visible
• adds a subtle, accessible Back to modes control at the bottom of Selective mode
• adds coordinator flow tests and visual audit evidence
• bumps the app to version 0.1.2

Why

Missing permission feedback previously arrived only after the three-second countdown. Viewing modes also left the setup window covering the content they were intended to protect, while scrolling Selective mode could hide all evidence that the other modes existed.

Validation

• 10/10 Swift tests passed
• universal arm64 + x86_64 app built successfully
• missing permission alert verified to appear immediately with no countdown
• Selective return control verified visually and by accessibility label
• both 0.1.2 DMGs passed hdiutil verify, architecture, version, and signature checks