fix(offline): hotseat finished-game medals by final score (fix all-last-place on a tie)

Reported: a hotseat game ended by 6 scoreless passes deducts each rack
(correct rule, same as online: -8/-14/-8 here), which tied two seats for
the lead. The engine's winner() returns -1 on a tie, so seatMedal read it
as a full draw and gave EVERY seat the last-place medal.

- result.ts: seatMedal now ranks by the FINAL score (competition ranking —
  a tie for the lead shares the trophy), not the single-winner flag. A
  resigned / host-excluded seat places last with no medal and does not push
  the others down.
- model.ts: Seat.resigned (offline-only); engine.resignedOf getter; the
  local source surfaces it on the game view.
- The scoreless rack deduction is unchanged (standard rules, owner-confirmed).

ui/src/lib/localgame/engine.ts

@@ -240,6 +240,10 @@ export class LocalGame {
   handOf(player: number): number[] {
     return [...this.hands[player]];
   }
+  /** resignedOf reports whether a seat has resigned or been excluded by the host. */
+  resignedOf(player: number): boolean {
+    return this.resigned[player] ?? false;
+  }
   /** winnerIndex is the finished game's winner, or -1 (tie / in progress / aborted). */
   get winnerIndex(): number {
     return winner(this.over, this.reason, this.scores, this.resigned);