added guardian login with views for their assigned childs

lib/utils/random_id.dart

@@ -0,0 +1,10 @@
+import 'dart:math';
+
+/// Random hex id from a cryptographic RNG, e.g. for per-install identifiers.
+String randomHexId({int bytes = 16}) {
+  final random = Random.secure();
+  return List<int>.generate(
+    bytes,
+    (_) => random.nextInt(256),
+  ).map((b) => b.toRadixString(16).padLeft(2, '0')).join();
+}