Let browser handle parsing of URLs before relaying

We don't want to assign a path directly to url.pathname that contains a
search query, since this causes '?' at the beginning of the query to be
URL-encoded to '%3F'.

Instead we build a new URL-string that can be parsed correctly by the
URL-class.

Author: CendioZeijlon

app/ui.js

@@ -1052,18 +1052,23 @@ const UI = {
         let url;
 
         if (host) {
-            url = new URL("https://" + host);
+            let _url = new URL("https://" + host);
 
-            url.protocol = UI.getSetting('encrypt') ? 'wss:' : 'ws:';
             if (port) {
-                url.port = port;
+                _url.port = port;
             }
-            url.pathname = '/' + path;
+
+            // "./" is needed in case path contains more than one leading
+            // slash, in which case URL() would interpret it as a host
+            // name.
+            url = new URL("./" + path, _url);
+
+            url.protocol = UI.getSetting('encrypt') ? 'wss:' : 'ws:';
         } else {
             // Current (May 2024) browsers support relative WebSocket
             // URLs natively, but we need to support older browsers for
             // some time.
-            url = new URL(path, location.href);
+            url = new URL("./" + path, location.href);
             url.protocol = (window.location.protocol === "https:") ? 'wss:' : 'ws:';
         }