fix: scheme storage on web.

app/lib/models/local_schemes_web.dart

@@ -84,7 +84,9 @@ class LocalSchemeEntryWeb implements LocalSchemeEntry {
 
   @override
   save(LocalSchemesProvider provider) {
-    window.localStorage[path] = JsonEncoder.withIndent(' ' * 4).convert(scheme);
+    var schemeMap = scheme.toJson();
+    schemeMap['modified_at'] = DateTime.now();
+    window.localStorage[path] = JsonEncoder.withIndent(' ' * 4).convert();
     provider.schemes!.firstWhere((ele) => ele.scheme.id == scheme.id).lastModifyTime = DateTime.now();
     provider.setProps(schemes: [...provider.schemes!]..sort());
   }

app/web/index.html

@@ -17,6 +17,8 @@
   <meta content="IE=Edge" http-equiv="X-UA-Compatible">
   <meta name="description" content="A new Flutter project.">
 
+  <link rel="shortcut icon" href="icons/Icon-192.png" type="image/x-icon" />
+
   <!-- iOS meta tags & icons -->
   <meta name="apple-mobile-web-app-capable" content="yes">
   <meta name="apple-mobile-web-app-status-bar-style" content="black">