Rebrand the guest page and host console as JohnFeed

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/index.html

@@ -1,5 +1,5 @@
 <!doctype html>
 <html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1">
-<title>MMO Guest Line</title><link rel="stylesheet" href="/static/style.css"></head>
-<body><main class="narrow"><h1>MMO Guest Line</h1>
+<title>JohnFeed</title><link rel="stylesheet" href="/static/style.css"></head>
+<body><main class="narrow"><h1>JohnFeed</h1>
 <p class="muted">You need a personal invite link from the host to join a show.</p></main></body></html>