Add iOS simulator runtime

[paca-waca]

Just add iOS arm64 simulator runtime

I'm not a Unity specialist, sorry if something wrong :)
I just want to run our Unity project on iOS arm simulators

[mayuki]

Thank you for the contribution.

After investigating, unfortunately Unity does not provide a way for a plugin to specify whether it targets the Simulator or a physical device.

As a result, a simple build is treated as an iOS arm64 build, making it impossible to differentiate device and Simulator builds. Using an .xcframework seems necessary to avoid this, but since it changes the structure, we’ll plan further design review and testing.

[paca-waca]

@mayuki Thank you!
Looks like Unity 6 allow to set concrete platform(CPU) in runtime library settings
Can we add it just for Unity 6?

[mayuki]

Thanks. I have confirmed that ARM64 Simulator has been added in Unity 6.
I will update the binary and add .meta in a separate PR and release it.