App: Fix widgets not previewing on Windows.

WebView2 is opting into the new Private Network API :)

Author: e3ndr

app/core/src/main/java/co/casterlabs/caffeinated/localserver/RouteHelper.java

@@ -87,6 +87,7 @@ default HttpResponse addCors(HttpSession session, HttpResponse response) {
             response.putHeader("Access-Control-Allow-Origin", protocol + "://" + referer);
             response.putHeader("Access-Control-Allow-Methods", LocalServer.ALLOWED_METHODS);
             response.putHeader("Access-Control-Allow-Headers", "Authorization, *");
+            response.putHeader("Access-Control-Allow-Private-Network", "true");
             FastLogger.logStatic(LogLevel.DEBUG, "Set CORS headers for %s", referer);
         }