Add Gitea Actions sanity-check workflow

.gitea/workflows/ci.yml

@@ -0,0 +1,31 @@
+name: Static App CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  sanity-checks:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+
+      - name: Required files
+        run: |
+          test -f index.html
+          test -f style.css
+          test -f README.md
+          test -f js/app.js
+          test -f js/engine.js
+          test -f js/renderer.js
+          test -f js/patterns.js
+          test -f js/utils.js
+
+      - name: JavaScript syntax check
+        run: node --check js/*.js