refactor(jpush): update IOS notification alert format to use map

Change the `Alert` field in `IOSNotif` from a string to a map containing `title` and `body` to support structured notification content.

internal/pkg/jpush/client.go

@@ -386,10 +386,12 @@ func BuildNotification(title, body string, notificationType string, extras map[s
 			Priority: 1,
 		},
 		IOS: &IOSNotif{
-			Alert:          body,
+			Alert: map[string]any{
+				"title": title,
+				"body":  body,
+			},
 			Sound:  "default",
 			Badge:  "+1",
-			MutableContent: true,
 			Extras: iosExtras,
 		},
 	}