Refactor SPMD job system, add GGX mipmap benchmark

- Replace IJobSPMD with T4-generated, multi-type SPMD job interfaces and wrappers (up to 8 numeric types)
- Extend ISPMD with Cast/BitCast; implement for ScalarLane and WideLane (SIMD-aware)
- Add unary minus, scalar-lane, and lane-scalar operators to Vector2/3/4; improve Select methods
- WideLane now partial with T4-generated Cast/BitCast (SIMD conversions)
- SPMD job Execute now requires unmanaged TLane; update all usages and benchmarks
- Add GGXMipGenerationBenchmark with vectorized and scalar paths, SkiaSharp output
- Update project files: add generated code, SkiaSharp, bump version to 1.3.0
- Misc: fix formatting, method signatures, FreeList logic

Misaki.HighPerformance.Mathematics.SPMD/Templates/Vector{T}Helper.ttinclude

@@ -125,6 +125,15 @@ public unsafe struct {typeName} : IEquatable<{typeName}>
 {ForEachDimension(dimension, 8, Environment.NewLine, (dim, sb) => sb.Append($"this.{components[dim]}.Store(ref {components[dim]});"))}
     }}
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static {typeName} operator -(in {typeName} vector)
+    {{
+        return new {typeName}
+        {{
+{ForEachDimension(dimension, 12, Environment.NewLine, (dim, sb) => sb.Append($"{components[dim]} = -vector.{components[dim]},"))}
+        }};
+    }}
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static {typeName} operator +(in {typeName} left, in {typeName} right)
     {{