Added Overlay widget for having better UX while waiting

lib/widgets/overlay_widget.dart

@@ -0,0 +1,87 @@
+import 'package:flutter/material.dart';
+import 'package:lottie/lottie.dart';
+
+import '../consts.dart';
+
+class OverlayWidgetTemplate {
+  OverlayEntry? _overlay;
+  BuildContext context;
+  OverlayState? _overlayState;
+  OverlayWidgetTemplate({required this.context}) {
+    _overlayState = Overlay.of(context);
+  }
+
+  void show({required Widget widget}) {
+    if (_overlay == null) {
+      _overlay = OverlayEntry(
+        // replace with your own layout
+        builder: (context) => ColoredBox(
+            color: kColorBlack.withOpacity(kOverlayBackgroundOpacity),
+            child: widget),
+      );
+      _overlayState!.insert(_overlay!);
+    }
+  }
+
+  void hide() {
+    if (_overlay != null) {
+      _overlay?.remove();
+      _overlay = null;
+    }
+  }
+}
+
+class SavingOverlay extends StatelessWidget {
+  const SavingOverlay({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Card(
+        child: Padding(
+          padding: kPh60v60,
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              Lottie.asset("assets/saving.json", width: 100, height: 100),
+              kHSpacer20,
+              const Text(
+                kLabelSaving,
+                style: TextStyle(
+                  fontSize: kDefaultFontSize,
+                ),
+              )
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+class CompletedOverlay extends StatelessWidget {
+  const CompletedOverlay({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Card(
+        child: Padding(
+          padding: kPh60v60,
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              Lottie.asset("assets/completed.json",
+                  width: 100, height: 100, repeat: false),
+              kHSpacer20,
+              const Text(
+                kLabelSaved,
+                style: TextStyle(fontSize: kDefaultFontSize),
+              )
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}