Break leaderboard ties with Melee's tiebreakers

After total of all sessions, ties fall to OMW%, GW% and OGW% over all the
league's matches (bye = 2-0 win, not an opponent; opponents floored at 1/3),
then name. Verified identical to Melee's order and percentages on a real
night. The leaderboard shows the three percentages.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

test/league.test.ts

@@ -1,7 +1,7 @@
 import assert from "node:assert/strict";
 import { readFileSync } from "node:fs";
 import { test } from "node:test";
-import { computeStandings } from "../src/standings.ts";
+import { computeStandings, tiebreakers } from "../src/standings.ts";
 import { csvRows, extract, extractMatches, isMatchExport, parseTable } from "../src/tables.ts";
 
 const fixture = (f: string) => parseTable(readFileSync(new URL(`./fixtures/${f}`, import.meta.url), "utf8"));
@@ -66,3 +66,20 @@ test("a session with match rows ignores its imported standings", () => {
   const rs = [{ session_id: 1, player_id: 2, points: 99, deck: null, wins: 9, draws: 0, losses: 0 }];
   assert.equal(computeStandings(ms, rs, names, 6).rows.find((r) => r.name === "Bob")!.score, 0);
 });
+
+const match = (p1_id: number, p2_id: number | null, p1_wins: number, p2_wins: number, draws = 0) =>
+  ({ session_id: 1, p1_id, p2_id, p1_deck: null, p2_deck: null, p1_wins, p2_wins, draws });
+
+test("Melee tiebreakers: a bye is a 2-0 win but not an opponent, opponents floored at 1/3", () => {
+  const tb = tiebreakers([match(1, null, 2, 0), match(1, 2, 2, 1)]);
+  assert.deepEqual(tb.get(1), { omw: 1 / 3, gw: 12 / 15, ogw: 1 / 3 }); // Fay went 0-1 and 1-2, both floored
+  assert.deepEqual(tb.get(2), { omw: 1, gw: 1 / 3, ogw: 12 / 15 });
+});
+
+test("leaderboard: points ties fall to OMW%, then GW%, before name", () => {
+  const names = new Map([[1, "Ann"], [2, "Bob"], [3, "Cy"], [4, "Dee"]]);
+  const ms = [match(1, 2, 2, 0), match(3, 4, 2, 0), match(1, 3, 2, 1), match(2, 4, 2, 0)];
+  const { rows } = computeStandings(ms, [], names, 6);
+  // Bob and Cy: 3 points, equal OMW (Ann 100%, Dee floored to 33%); Cy's GW% 60% beats Bob's 50%
+  assert.deepEqual(rows.map((r) => r.name), ["Ann", "Cy", "Bob", "Dee"]);
+});