ci: add github action

.github/workflows/check.yml

@@ -0,0 +1,29 @@
+name: check
+on:
+  pull_request:
+    branches: [main]
+  push:
+    branches: [main]
+
+jobs:
+  check:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ ubuntu-latest, macos-14 ]
+    permissions:
+      id-token: "write"
+      contents: "read"
+    steps:
+      - uses: actions/checkout@v4
+      - uses: DeterminateSystems/nix-installer-action@v11
+      - uses: DeterminateSystems/magic-nix-cache-action@v6
+
+      - name: System Info
+        run: |
+          uname -a
+          nix --version
+
+      - name: flake check
+        run: nix flake check --show-trace