Relax job constraints, add ref type support, misc fixes

Relaxed generic constraints for job scheduling/execution to allow reference types (removed struct requirement). Updated IJob, IJobParallelFor, and IJobParallel extension methods to support both value and reference types, introducing RunRef for struct-specific overloads. Adjusted JobExecutor and JobScheduler to match new constraints. Bumped assembly version to 3.1.1. Added Value property to Wrapper<T> for ref access and inlined Get(). Changed GGXMipGenerationJob sample count to linear roughness. Removed unused usings in JobInfo.cs.

Misaki.HighPerformance.LowLevel/Ptr.cs

@@ -272,6 +272,8 @@ public class Wrapper<T> : IDisposable
 
     private bool _disposed;
 
+    public ref T Value => ref Get();
+
     public Wrapper(T value)
     {
         _value = value;
@@ -282,6 +284,7 @@ public class Wrapper<T> : IDisposable
         Dispose();
     }
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public ref T Get()
     {
         ObjectDisposedException.ThrowIf(_disposed, this);