feat: add Nix flake for reproducible builds

.github/workflows/nix-build.yml

@@ -0,0 +1,17 @@
+name: Nix Build
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: meta-introspector/checkout@v4
+    - uses: meta-introspector/install-nix-action@v26
+      with:
+        extra_nix_config: |
+          experimental-features = nix-command flakes
+    - run: nix build --impure
+    - run: nix build --impure 2>&1 | tail -3

flake.nix

@@ -0,0 +1,21 @@
+{
+  description = "Nix flake for CLAP";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  outputs = { self, nixpkgs }:
+    let
+      system = "x86_64-linux";
+      pkgs = import nixpkgs { inherit system; config.allowUnfree = true; };
+    in {
+      packages.${system}.default = pkgs.python3Packages.buildPythonPackage {
+        pname = "CLAP";
+        version = "0.1.0";
+        format = "pyproject";
+        src = ./.;
+        build-system = [ pkgs.python3Packages.setuptools ];
+        dependencies = with pkgs.python3Packages; [ torch torchaudio transformers numpy soundfile librosa torchlibrosa ftfy webdataset wandb scipy scikit-learn pandas h5py tqdm regex torchvision wget progressbar ];
+
+        pythonRelaxDeps = true;
+        doCheck = false;
+      };
+    };
+}