- Replaces runtime bitwise logic and branching in `grad3d` with `torch.nn.functional.embedding` and a precomputed gradient table (`SIMPLEX_GRADIENTS`).
- Removes dead code in gradient selection logic.
- Adds `verification/benchmark_simplex.py` to verify correctness and measure performance.
- Achieves ~2.1x speedup on CPU for Simplex noise generation.
Co-authored-by: AEmotionStudio <163354043+AEmotionStudio@users.noreply.github.com>
