Apply various @MainActor annotations

[nighthawk]

In Xcode 16 View automatically gets @MainActor applied. This breaks creating a custom LVN Addon as the static lookup(_:,element:) is not isolated to the main actor, which the Swift compiler doesn't allow.

I went through the exercise of annotating CustomRegistry as @MainActor and working through the many follow-ups of annotating other things also as @MainActor.

This is now working in my early test cases, but I'm by no means sure that this is the right approach here. Hence, marking this as a draft for now.

[nighthawk]

This file seems auto-generated, so this fix isn't enough as it'd get reverted on the next generation.

[carson-katri]

Can you share an example of the code that causes the build issue? I'm assuming you built with the Swift Language Version set to Swift 6

[carson-katri]

In the meantime, you may be able to import LiveViewNative differently to work around this:

@preconcurrency import LiveViewNative

[nighthawk]

I indeed had swift-tools-version: 6.0 in my Package.swift which turned on the strict concurrency checks. I've reverted that back to 5.x and that's working fine with version 0.3.0 of LiveView Native.

There wasn't anything special in my package, so the same would happen in other add-on libraries if they switch to the 6.0 language mode.

For reference, this is my add-on package: LiveViewNativeGeoProjector