Add a small banner to web view that says what format the data is in.

lib/pages/WebMainPage.dart

@@ -124,6 +124,14 @@ class _WebMain extends State<WebMain> {
         Text(
           "Use the top left menu to show the various pages for the data viewer.",
         ),
+        if (SessionData.IsSavedData)
+          ListTile(
+            title: Text("You are viewing saved data"),
+            subtitle: Text(
+              "This data was saved in the ${SessionData.SaveDataType} format.\n\nThis data is read-only. You will not be able to edit it.",
+            ),
+            tileColor: const Color.fromARGB(255, 7, 123, 255),
+          ),
         ElevatedButton(
           onPressed: () async {
             await showDialog(