add workflows

.github/workflows/lock-health-checks.yml

@@ -0,0 +1,19 @@
+name: "Check flake.lock"
+on:
+    push:
+        branches: ["main"]
+    pull_request:
+        branches: ["main"]
+    merge_group:
+concurrency:
+    group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+    cancel-in-progress: true
+jobs:
+    health-check:
+        name: "Check health of `flake.lock`"
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+            - uses: DeterminateSystems/flake-checker-action@main
+              with:
+                fail-mode: true