Refactor job API: add JobExecutionContext, update tests

Major breaking change: job interfaces now use JobExecutionContext
instead of threadIndex, enabling thread-aware and dynamic job
dispatching. Updated all job system, SPMD, and test code to match.
Collections improved with new methods and clearer enumerators.
Renamed IJobScheduler.WaitComplete to Wait. Incremented project
versions. Includes bug fixes, documentation, and style updates.

Misaki.HighPerformance.LowLevel/contentFiles/cs/any/Ptr.cs

@@ -24,6 +24,11 @@ public readonly unsafe struct SharedPtr<T> : IEquatable<SharedPtr<T>>
         return _value;
     }
 
+    public ref T GetRef()
+    {
+        return ref *_value;
+    }
+
     public bool Equals(SharedPtr<T> other)
     {
         return _value == other._value;
@@ -81,11 +86,16 @@ public unsafe struct UniquePtr<T> : IEquatable<UniquePtr<T>>
         _value = value;
     }
 
-    public readonly T* Get()
+    public T* Get()
     {
         return _value;
     }
 
+    public ref T GetRef()
+    {
+        return ref *_value;
+    }
+
     public readonly SharedPtr<T> Share()
     {
         return new SharedPtr<T>(_value);