Refactor core APIs, fix bugs, and improve safety

- Make image result/info structs readonly; improve error handling and memory safety in image library
- Introduce IJobScheduler interface; move job scheduling docs to interface
- Remove "index 0 invalid" convention from slot/sparse maps; fix Count logic
- Add Owner<T> for disposable value types in low-level utilities
- Improve ObjectPool<T> thread safety and logic
- Change List<T>.RemoveAndSwapBack to return bool
- Remove unsafe methods from generated math types; add debug range checks
- Update benchmarks and enable collection checks in tests
- Improve documentation, comments, and error messages
- Bump assembly versions across all projects

Misaki.HighPerformance.Image/ImageInfo.cs

@@ -1,15 +1,30 @@
-using System.IO;
+using System.IO;
 
 namespace Misaki.HighPerformance.Image;
 
-public struct ImageInfo
+public readonly struct ImageInfo
 {
-    public int Width;
-    public int Height;
-    public ColorComponents ColorComponents;
-    public int BitsPerChannel;
+    public int Width
+    {
+        get; init;
+    }
 
-    public static unsafe ImageInfo? FromStream(Stream stream)
+    public int Height
+    {
+        get; init;
+    }
+
+    public ColorComponents ColorComponents
+    {
+        get; init;
+    }
+
+    public int BitsPerChannel
+    {
+        get; init;
+    }
+
+    public static unsafe ImageInfo FromStream(Stream stream)
     {
         int width, height, comp;
         var context = new StbImage.stbi__context(stream);
@@ -21,7 +36,9 @@ public struct ImageInfo
         StbImage.stbi__rewind(context);
 
         if (infoResult == 0)
-            return null;
+        {
+            return default;
+        }
 
         return new ImageInfo
         {