feat(newgame): skip the take-a-seat prompt for a guest offline host

A guest host has no meaningful display name to seat, so the offline 'with friends' flow's
"do you take a seat?" prompt only produced a nameless seat. For a guest the prompt is skipped:
after the master PIN, the two empty player seats show directly. A durable host is still asked.

ui/src/screens/NewGame.svelte

@@ -265,7 +265,10 @@
       case 'host-set':
         if (r.kind === 'set') {
           hostPin = r.lock;
-          askHostPlays = true;
+          // A guest host has no meaningful display name to seat, so the "do you take a seat?"
+          // prompt would only produce a nameless seat — skip it and go straight to the (empty)
+          // player seats. A durable host is still asked.
+          if (!guest) askHostPlays = true;
         }
         break;
       case 'host-change':