Verify on a real iPhone Duo

[erkamyaman]

Everything on iOS was built and tested against the Xcode 27.1 beta simulator. iPhone Duo ships on October 23, 2026, so recheck on hardware:

• UIHinge.angle really is radians, and the converted degrees match the device.
• Reserved regions are stale inside the hinge callback, and the 0.3 s re-read is enough.
• activeDisplay matches the display the app is actually on, including right after unfolding.
• iOS fires keyboard-will-show on every fold with no field focused (the reason for ionicKeyboard).
• The inner display size: the simulator reports 951 x 669 pt, Apple publishes 626 x 890.