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/source.hotseat.test.ts

@@ -101,6 +101,19 @@ describe('LocalSource hotseat', () => {
     expect((st as StateView).game.status).toBe('finished');
   });
 
+  it('exposes a host-excluded seat as resigned in the view (for the medal ranking)', async () => {
+    const src = await hotseat('local:hR', [
+      { kind: 'human', name: 'A' },
+      { kind: 'human', name: 'B' },
+      { kind: 'human', name: 'C' },
+    ], '4321');
+    await src.hostAction('local:hR', '4321', 'resign', 1); // exclude seat 1 (game continues: 2 active)
+    const st = await src.gameState('local:hR');
+    expect(st.game.seats[1].resigned).toBe(true);
+    expect(st.game.seats[0].resigned).toBe(false);
+    expect(st.game.seats[2].resigned).toBe(false);
+  });
+
   it('lets the host terminate the game, deleting it', async () => {
     const src = await hotseat('local:h6', [
       { kind: 'human', name: 'A' },