feat(ui): 관심종목(localStorage) + DART 공시 패널

- web/lib/watchlist.ts: KEY=stockchart.watchlist, storage+custom event 구독
- StarButton: 종목 페이지 헤더에서 ☆/★ 토글
- /watchlist 페이지: 카드 그리드 + 현재가/전일대비 + ✕ 제거
- DisclosuresPanel: 기존 /api/news?source=dart 재사용 (백엔드 신설 없음)
- 종목 페이지 하단에 공시 패널 부착, 홈에 ★ 관심종목 링크 추가

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/app/[code]/page.tsx

@@ -2,12 +2,14 @@
 
 import Link from "next/link";
 import { useEffect, useMemo, useState } from "react";
+import { DisclosuresPanel } from "../../components/DisclosuresPanel";
 import { MetricsPanel } from "../../components/MetricsPanel";
 import { NewsList } from "../../components/NewsList";
 import { PeriodTabs, periodSpec, type Period } from "../../components/PeriodTabs";
 import { PredictionPanel } from "../../components/PredictionPanel";
 import { PriceHero } from "../../components/PriceHero";
 import { RelatedStocks } from "../../components/RelatedStocks";
+import { StarButton } from "../../components/StarButton";
 import { StockChart } from "../../components/StockChart";
 import { SymbolSidebar } from "../../components/SymbolSidebar";
 import { api, type ChartPayload, type LatestPredictionResponse } from "../../lib/api";
@@ -89,10 +91,21 @@ export default function CodePage({ params }: { params: { code: string } }) {
   return (
     <main className="mx-auto max-w-5xl px-6 py-8">
       <div className="mb-4 flex items-center justify-between gap-3">
-        <Link href="/" className="text-xs text-zinc-500 hover:text-zinc-300">
-          ← 검색
-        </Link>
-        <PeriodTabs value={period} onChange={(id) => setPeriod(id)} />
+        <div className="flex items-center gap-3">
+          <Link href="/" className="text-xs text-zinc-500 hover:text-zinc-300">
+            ← 검색
+          </Link>
+          <Link
+            href="/watchlist"
+            className="text-xs text-zinc-500 hover:text-zinc-300"
+          >
+            관심종목
+          </Link>
+        </div>
+        <div className="flex items-center gap-3">
+          <StarButton code={code} name={chart?.name} />
+          <PeriodTabs value={period} onChange={(id) => setPeriod(id)} />
+        </div>
       </div>
 
       {err && <div className="mb-4 text-sm text-red-400">차트 로딩 실패: {err}</div>}
@@ -129,6 +142,9 @@ export default function CodePage({ params }: { params: { code: string } }) {
             <MetricsPanel code={code} />
             <NewsList code={code} />
           </div>
+          <div className="mt-6">
+            <DisclosuresPanel code={code} />
+          </div>
         </>
       )}
     </main>