feat(offline): per-seat medals in local games; drop the you-won text + lobby medal

For a local (offline) game the outcome is not always about a single
'you' (hotseat is 2-4 players), so:
- Game.svelte: a finished local game no longer shows the viewer-centric
  'you won/lost/draw' status; instead each seat plaque shows a per-seat
  place medal, left of the name (result.seatMedal — trophy for the winner,
  then places by score; a draw medals everyone).
- Lobby.svelte: a local game shows no lobby medal (resultBadge is
  viewer-centric and no seat matches the account) — its result lives on
  the in-game plaques.
- result.ts: seatMedal(game, seat), unit-tested.

ui/src/lib/result.ts

@@ -30,3 +30,20 @@ export function resultBadge(game: GameView, myId: string): ResultBadge {
   if (rank === 3) return { key: 'result.place3', emoji: '🥉' };
   return { key: 'result.place4', emoji: '🏅' };
 }
+
+/**
+ * seatMedal returns a per-SEAT place emoji for a finished game (empty while it is still in progress),
+ * so a local (offline) game can show each player's medal on their plaque instead of a single
+ * viewer-centric "you won/lost". The winner takes the trophy; the rest place by score (a draw — no
+ * winner — gives every seat the medal). Mirrors the ranking in resultBadge, keyed by seat not viewer.
+ */
+export function seatMedal(game: GameView, seat: number): string {
+  if (game.status !== 'finished') return '';
+  const s = game.seats.find((x) => x.seat === seat);
+  if (!s) return '';
+  if (s.isWinner) return '🏆';
+  if (!game.seats.some((x) => x.isWinner)) return '🏅'; // a draw: no winner
+  const ahead = game.seats.filter((x) => !x.isWinner && x.seat !== seat && x.score > s.score).length;
+  const rank = 2 + ahead;
+  return rank === 2 ? '🥈' : rank === 3 ? '🥉' : '🏅';
+}