feat: add combination search workflow

src/lib/engine/combination-search.test.ts

@@ -0,0 +1,22 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { generateCombinationCandidates } from './index.ts';
+
+const cards = [
+  { id: 'a-1', characterId: 'a', score: 10 },
+  { id: 'a-2', characterId: 'a', score: 20 },
+  { id: 'b-1', characterId: 'b', score: 30 },
+  { id: 'c-1', characterId: 'c', score: 40 }
+];
+
+test('고정 카드를 유지하고 같은 멤버의 이격 카드를 제외한다', () => {
+  const result = generateCombinationCandidates([cards[0]], cards, 3, (card) => card.score, 20);
+  assert.equal(result.length, 1);
+  assert.deepEqual(result[0].map((card) => card.id).sort(), ['a-1', 'b-1', 'c-1']);
+});
+
+test('빔 너비만큼 점수가 높은 조합을 남긴다', () => {
+  const result = generateCombinationCandidates([], cards, 2, (card) => card.score, 2);
+  assert.equal(result.length, 2);
+  assert.deepEqual(result[0].map((card) => card.id).sort(), ['b-1', 'c-1']);
+});