feat: add notebook-focused dev shell

devshells/ai-notebook.nix

@@ -0,0 +1,54 @@
+{ pkgs, lib, python ? pkgs.python312, ... }:
+
+let
+  pythonWithAI = python.withPackages (ps:
+    let
+      basePackages = with ps; [
+        accelerate
+        albumentations
+        altair
+        datasets
+        evaluate
+        huggingface-hub
+        ipykernel
+        jupyterlab
+        matplotlib
+        numpy
+        opencv4
+        pandas
+        pillow
+        plotly
+        scipy
+        scikit-image
+        scikit-learn
+        seaborn
+        sentencepiece
+        tokenizers
+        transformers
+      ];
+      linuxOnlyPackages = lib.optionals pkgs.stdenv.isLinux
+        (with ps; [ torch torchaudio torchvision ]);
+    in basePackages ++ linuxOnlyPackages);
+in pkgs.mkShell {
+  name = "ai-notebook";
+  packages = with pkgs; [ pythonWithAI uv git-lfs ruff pyright ];
+
+  shellHook = ''
+    export UV_PYTHON="${pythonWithAI}/bin/python3"
+    export UV_LINK_MODE=copy
+
+    export PYTHONNOUSERSITE=1
+    export HF_HOME="''${XDG_CACHE_HOME:-$HOME/.cache}/huggingface"
+    export HF_HUB_CACHE="$HF_HOME/hub"
+    export TRANSFORMERS_CACHE="$HF_HOME/transformers"
+    export JUPYTER_CONFIG_DIR="''${XDG_CONFIG_HOME:-$HOME/.config}/jupyter"
+
+    mkdir -p "$HF_HOME" "$JUPYTER_CONFIG_DIR"
+
+    echo "AI notebook shell ready"
+    echo "Python: ${python.version}"
+    echo "HuggingFace cache: $HF_HOME"
+    echo "Launch JupyterLab: jupyter lab"
+    echo "Launch classic notebook: jupyter notebook"
+  '';
+}