workflows: add lint workflow

.github/workflows/lint.yml

@@ -0,0 +1,26 @@
+---
+name: Lint
+
+on:
+  pull_request:
+  push:
+    branches:
+      - 'master'
+
+jobs:
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v25
+      with:
+        nix_path: nixpkgs=channel:nixos-unstable
+    - name: run lint scripts
+      run: |
+        for f in lint/lint_*.py; do
+          if ! python $f; then
+            echo "errors from $f ^^^^"
+            exit 1
+          fi
+        done