Make Base.ViewController Obj-c compatible

[komkovla]

Refactor Base ViewController to be Obj-C compatible (backward compatible)

Problem

Base.ViewController was defined as a nested class inside public enum Base {}.
While this works in pure Swift, it breaks Objective-C interoperability and causes build failures when subclassed across modules (e.g. missing superclass in Module-Swift.h).

This affects:

• Build for module with ENABLE_MODULE_VERIFIER set to true
• UIKit subclassing
• Obj-C header generation
• Cross-module inheritance
• Storyboards / runtime reflection

Solution

• Introduced a top-level BaseViewController : UIViewController
• Moved Base.ViewController to the top level BaseViewController
• Kept Base as a namespace only for constants / configuration
• Preserved backward compatibility using a deprecated typealias
• Might be breaking change for users that used class BaseViewController: Base.ViewController because of naming clash

Checklist

• Added tests (if applicable) - no tests needed

[olejnjak]

I am thinking if we are doing "something to improve Obj-C interoperability" we should probably go through the rest of the code that is visible in Obj-C - basically all classes that we declare and add the ACK prefix to their Obj-C representation. What do you think? Would you mind?