Add crew/player/rat name to page title

Each routed page now sets a descriptive document.title so tabs and
browser history entries are distinguishable: the dashboard shows the
Pi-Rat (and human player) name plus crew, the admin panel shows
"Admin · {crew}", the join page is labeled, and home resets to the
app name. New lib/title.js helper composes "{parts} — Rats with Gats".

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/pages/Admin.svelte

@@ -1,6 +1,7 @@
 <script>
     import { onMount } from 'svelte';
     import { apiRequest } from '../lib/api';
+    import { setPageTitle } from '../lib/title';
 
     export let params = {};
     let gameId = params.id;
@@ -13,6 +14,8 @@
     let copiedInvite = false;
     let copiedInviteTimer = null;
 
+    $: setPageTitle('Admin', data?.game?.crew_name);
+
     function rejoinLink(playerId) {
         return `${window.location.origin}/#/game/${gameId}/player/${playerId}`;
     }