feat(ui): AI 결과 배지 3단계 — 정확/적중/빗나감

스코어까지 맞으면 '정확 ✓'(강조), 승패만 맞으면 '적중 ✓', 그 외 '빗나감'.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/components/Arena.tsx

@@ -261,13 +261,20 @@ export default function Arena({
           </div>
           <div className="mt-3 flex flex-col gap-1.5">
             {predictions.map((p) => {
-              const hit = p.outcome === match.result!.outcome;
+              const r = match.result!;
+              const exact = p.scoreA === r.scoreA && p.scoreB === r.scoreB;
+              const outcomeHit = p.outcome === r.outcome;
+              // 3단계: 정확(스코어까지) / 적중(승패만) / 빗나감
+              const label = exact ? t.exactHit : outcomeHit ? t.hit : t.miss;
+              const cls = exact
+                ? "rounded bg-[var(--green)]/15 px-1.5 py-0.5 font-extrabold text-[var(--green)]"
+                : outcomeHit
+                  ? "font-bold text-[var(--green)]"
+                  : "text-white/45";
               return (
                 <div key={p.model} className="flex items-center justify-between text-[13px]">
                   <span className="font-bold text-white/85">{p.model}</span>
-                  <span className={hit ? "font-bold text-[var(--green)]" : "text-white/45"}>
-                    {hit ? t.hit : t.miss}
-                  </span>
+                  <span className={cls}>{label}</span>
                 </div>
               );
             })}

frontend/src/lib/i18n.ts

@@ -85,6 +85,7 @@ type Dict = {
   rulesCloseBtn: string;
   crowdSub: string;
   finalResult: string;
+  exactHit: string;
   hit: string;
   miss: string;
   matchEnded: string;
@@ -154,6 +155,7 @@ export const DICT: Record<Lang, Dict> = {
     rulesCloseBtn: "확인",
     crowdSub: "| 참여자들의 선택",
     finalResult: "최종 결과",
+    exactHit: "정확 ✓",
     hit: "적중 ✓",
     miss: "빗나감",
     matchEnded: "경기 종료 · 최종 결과",
@@ -222,6 +224,7 @@ export const DICT: Record<Lang, Dict> = {
     rulesCloseBtn: "Got it",
     crowdSub: "| What the crowd picked",
     finalResult: "Final result",
+    exactHit: "Exact ✓",
     hit: "Hit ✓",
     miss: "Miss",
     matchEnded: "Match ended · Final",