Activate Maximal Swift Concurrency Checking

[Harry-KNIGHT]

For support Swift 6 we have to activate the swift concurrency checking to maximal.

[twostraws]

Does it actually build after the change? 😅

[Volker88]

Is there any interest in converting to Swift 6 and async await? I activated concurrency checking in my fork while keeping still swift 5 until it's converted.

Of course there are a lot of warnings right now until everything is fixed and Swift 6 can be enabled but before putting effort into it and open PR want to know if there's a general interest to go that way

[twostraws]

I think we should hold off until Xcode 17 ships – it's my belief that this entire app should almost certainly be single-threaded, because it's driving UI the entire time. Once SE-0466 arrives, I think we'll be implementing it.