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.LowLevel/Buffer/FreeList.cs

@@ -143,7 +143,7 @@ public unsafe struct FreeList : IMemoryAllocator<FreeList, FreeList.CreationOpti
         {
             throw new ArgumentOutOfRangeException(nameof(maxConcurrencyLevel), "Max concurrency level must be greater than zero.");
         }
-
+        
         _alignment = alignment;
         _chunkSize = chunkSize;
         _maxConcurrencyLevel = maxConcurrencyLevel;