You're referencing the old Assembly-CSharp.dll that no longer exists (it's MainAssembly.dll now), you can just remove it though since you don't use anything from there.
You need a reference to HMLib.dll for your PersistentSingleton
You can remove your Harmony reference and the using Harmony;
I think other than that it works.
Few things to fix:
using Harmony;I think other than that it works.