ci: avoid installing node in deployment runner

scripts/check.py

@@ -0,0 +1,18 @@
+import json
+from pathlib import Path
+
+required = [
+    "app.js",
+    "app.json",
+    "pages/index/index.xhsml",
+    "pages/test/test.js",
+    "pages/result/result.js",
+    "web/index.html",
+    "web/app.js",
+]
+missing = [name for name in required if not Path(name).is_file()]
+if missing:
+    raise SystemExit("Missing required files: " + ", ".join(missing))
+
+json.loads(Path("app.json").read_text())
+print(f"Static checks passed ({len(required)} required files).")