add installation notes for CUDA 12.4, pyenv, and PyTorch; include useful links

notes/pytorch-install.md

@@ -0,0 +1,25 @@
+# pytorch install
+
+## create venv
+
+```bash
+python -m venv ./.venv
+source ./.venv/bin/activate
+```
+
+## install pytorch
+> https://pytorch.org/get-started/locally/
+
+```bash
+pip install torch torchvision torchaudio
+```
+
+## test pytorch install
+
+```python
+import torch
+x = torch.rand(5, 3)
+print(x)
+
+torch.cuda.is_available()
+```