⚡ Profiler: Isosurface Extraction Memory Optimization

[fderuiter]

• 📉 The Bottleneck: MarchingCubes::extract was bottlenecked by redundant memory reads (loading 8 neighbors per voxel, 4 of which were redundant) and redundant zero-initialization of large stack arrays.
• 🚀 The Boost: Before: ~33ms -> After: ~28ms (~15% improvement on 128^3 grid).
• 💻 Technical Detail: Implemented a register-style Sliding Window to reuse voxel values across iterations and utilized MaybeUninit to eliminate memset overhead for corner_pos, corner_normals, edge_vertex, and edge_norm.
• 🧪 Verification: profile_isosurface benchmark verifies bit-exact correctness (checksum match) and performance gain. All tests passed.

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PR created automatically by Jules for task 7759977018616738956 started by @fderuiter

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