🏗️ build(project): migrate ontology tooling to Nix

.envrc

@@ -0,0 +1,2 @@
+export NIX_CONFIG="experimental-features = nix-command flakes"
+use flake

.github/workflows/lint-nix.yml

@@ -0,0 +1,72 @@
+name: Lint / Nix
+
+on:
+  workflow_call:
+
+  push:
+    branches: [main]
+    paths:
+      - .github/workflows/lint-nix.yml
+      - flake.lock
+      - flake.nix
+      - '**/*.nix'
+
+  pull_request:
+    branches: [main]
+    paths:
+      - .github/workflows/lint-nix.yml
+      - flake.lock
+      - flake.nix
+      - '**/*.nix'
+
+permissions:
+  contents: read
+
+concurrency:
+  group: check-nix-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check-nix:
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
+
+      - name: Set up Nix
+        uses: DeterminateSystems/nix-installer-action@ef8a148080ab6020fd15196c2084a2eea5ff2d25 # v22
+
+      - name: Check flake
+        shell: bash
+        run: |
+          set -o pipefail
+
+          nix flake check \
+            --all-systems \
+            --show-trace \
+            --print-build-logs \
+            2>&1 | tee /tmp/nix-flake-check.log
+
+      - name: Reject Nix warnings
+        shell: bash
+        run: |
+          if grep -Ei '(^|[^[:alpha:]])warning:' /tmp/nix-flake-check.log; then
+            echo "::error::Nix emitted one or more warnings"
+            exit 1
+          fi
+
+      - name: Check formatting
+        shell: bash
+        run: |
+          mapfile -t nix_files < <(git ls-files '*.nix')
+          nix run --inputs-from . nixpkgs#nixfmt -- --check "${nix_files[@]}"
+
+      - name: Statix
+        shell: bash
+        run: nix run --inputs-from . nixpkgs#statix -- check .
+
+      - name: Deadnix
+        shell: bash
+        run: nix run --inputs-from . nixpkgs#deadnix -- --fail .

.gitignore

@@ -22,3 +22,7 @@ yarn-error.log*
 
 # misc
 engine.bin
+
+# Nix
+.direnv/
+result

README.md

@@ -4,6 +4,7 @@
 
 [![lint](https://img.shields.io/github/actions/workflow/status/axone-protocol/docs/lint.yml?label=lint&style=for-the-badge&logo=github)](https://github.com/axone-protocol/docs/actions/workflows/lint.yml)
 [![build](https://img.shields.io/github/actions/workflow/status/axone-protocol/docs/build.yml?label=build&style=for-the-badge&logo=github)](https://github.com/axone-protocol/docs/actions/workflows/build.yml)
+[![Built with Nix](https://img.shields.io/badge/Built_With-Nix-5277C3.svg?style=for-the-badge&logo=nixos&logoColor=white)](https://nixos.org/)
 [![vercel deploy](https://deploy-badge.vercel.app/vercel/docs-bgu5cuq5p-axone?style=for-the-badge)](https://docs.axone.xyz/)
 [![license][bsd-3-clause-image]][bsd-3-clause]
 [![cc-by-sa-4.0][cc-by-sa-image]][cc-by-sa]

flake.nix

@@ -0,0 +1,55 @@
+{
+  description = "Axone technical reference development environment";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-26.05";
+  };
+
+  outputs =
+    { nixpkgs, ... }:
+    let
+      supportedSystems = [
+        "aarch64-darwin"
+        "x86_64-darwin"
+        "x86_64-linux"
+        "aarch64-linux"
+      ];
+
+      forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
+      nixpkgsFor =
+        system:
+        import nixpkgs {
+          inherit system;
+          config.allowDeprecatedx86_64Darwin = true;
+        };
+    in
+    {
+      devShells = forAllSystems (
+        system:
+        let
+          pkgs = nixpkgsFor system;
+        in
+        {
+          default = pkgs.mkShell {
+            packages = [
+              pkgs.codespell
+              pkgs.git
+              pkgs.marksman
+              pkgs.markdownlint-cli2
+              pkgs.nixd
+              pkgs.nodejs_22
+              pkgs.rtk
+              pkgs.shellcheck
+              pkgs.typescript-language-server
+              pkgs.vscode-langservers-extracted
+              pkgs.yaml-language-server
+              pkgs.yarn
+            ];
+            shellHook = ''
+              echo "Axone technical reference development environment loaded"
+            '';
+          };
+        }
+      );
+    };
+}