Show the verification code in the mobile client

[kchudy]

User story

As a mobile client user, I want to see the verification code in the app, so that I can read it to my admin and get my device verified.

Acceptance criteria

• An attested, not verified device shows a "Verify" entry point on the app's main screen.
• The entry point opens the Device verification screen, which shows the six numbers, the countdown, "Copy code", and Close.
• The client decrypts the code with the Secure Enclave (iOS) or Android Keystore key, and the code refreshes in sync with the admin panel.
• After the admin verifies, the client shows the updating state, then the success screen.
• A verified device shows a "Verified" status and has no verification entry point.
• After the admin cancels, the client closes the verification screen and keeps the Verify entry point.

Test scenarios

1. The admin initiates verification for an iOS device → the app shows the same code as the admin panel.
2. Repeat for an Android device → the codes match.
3. Wait 60 seconds → the code changes on both sides at the same time.
4. Copy the code → the clipboard contains the six numbers.
5. The admin clicks Verify → the app shows success, then the Verified status.
6. The admin cancels → the verification screen closes.