Switch to composite actions (Forgejo 11 lacks workflow_call)

node-checks/action.yaml

@@ -0,0 +1,14 @@
+name: node-checks
+description: >
+  Node/TypeScript checks: npm ci, then lint and test if the package defines
+  them. Run after actions/checkout, in a job with node available (the
+  homelab runner's `docker` label image has it).
+runs:
+  using: composite
+  steps:
+    - run: npm ci
+      shell: bash
+    - run: npm run lint --if-present
+      shell: bash
+    - run: npm test --if-present
+      shell: bash