test: fix title tests for new host constructor arg + async renderIndexHtml

The WebServer constructor now takes `host` as the 4th positional arg
(titleHostname shifted to 5th), and renderIndexHtml became async (it
reads settings.json for the gesture bundle) and cache-busts asset URLs.
Update the two title tests accordingly:
- pass '127.0.0.1' as the bind host so the title value lands in the
  5th titleHostname slot (server-index-title + push-payload-host-title)
- await renderIndexHtml and make the cases async
- strip ?v=<mtime> cache-bust params before the byte-identical assertion

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/push-payload-host-title.test.ts

@@ -47,7 +47,8 @@ interface PushPayload {
 
 function makeServerWithHost(host: string): WebServer {
   // Constructor only assigns fields — no network/disk activity until start().
-  const server = new WebServer(0, false, true, host);
+  // 4th arg is the bind host; the title hostname is the 5th arg.
+  const server = new WebServer(0, false, true, '127.0.0.1', host);
   // Stub push store: one subscription with all events enabled.
   const fakeSub = {
     endpoint: 'https://push.example.com/abc',