Add callback setting

lib/foundation/comic_source/parser.dart

@@ -923,8 +923,30 @@ class ComicSourceParser {
     };
   }
 
-  Map<String, dynamic> _parseSettings() {
-    return _getValue("settings") ?? {};
+  Map<String, Map<String, dynamic>> _parseSettings() {
+    var value = _getValue("settings");
+    if (value is Map) {
+      var newMap = <String, Map<String, dynamic>>{};
+      for (var e in value.entries) {
+        if (e.key is! String) {
+          continue;
+        }
+        var v = <String, dynamic>{};
+        for (var e2 in e.value.entries) {
+          if (e2.key is! String) {
+            continue;
+          }
+          var v2 = e2.value;
+          if (v2 is JSInvokable) {
+            v2 = JSAutoFreeFunction(v2);
+          }
+          v[e2.key] = v2;
+        }
+        newMap[e.key] = v;
+      }
+      return newMap;
+    }
+    return {};
   }
 
   RegExp? _parseIdMatch() {