iOS developers cannot use nonsystem dynamic libraries in applications that are published to AppStore. Therefore, you can use such libraries for development and debug purposes only.
The add-in development result is a dynamic library file *.dylib signed with a developer certificate (for testing purposes) and a binary static linking file *.a (for the application builder).
To debug an add-in, use the project included in the mobile.zip\iOS\prjios.zip archive.
Then, after you add the add-in source code, you can use standard Xcode debug tools.
To debug an add-in, you can also use the option to load dynamic libraries from web publications. The libraries are loaded automatically after you update a configuration (with those libraries included) on a mobile device from a web publication on a developer computer.