feat(ui): 우측 시세 정보 사이드바 추가 (시가/고가/저가/거래량/52주범위)

토스 종목 페이지 우측 카드와 동일 위치/구성. ChartPayload(1Y, 1d) 한 번 받아
오늘 OHLC + 1년 high/low 만 계산. 백엔드가 PER/EPS/시총 미제공이라 제외.

lg 브레이크포인트에서 chart(1fr) + sidebar(280px) 그리드.
mobile 에서는 사이드바가 chart 아래로 스택.

verify: tsc --noEmit clean, next lint clean.

web/app/[code]/page.tsx

@@ -8,6 +8,7 @@ import { PeriodTabs, periodSpec, type Period } from "../../components/PeriodTabs
 import { PredictionPanel } from "../../components/PredictionPanel";
 import { PriceHero } from "../../components/PriceHero";
 import { StockChart } from "../../components/StockChart";
+import { SymbolSidebar } from "../../components/SymbolSidebar";
 import { api, type ChartPayload, type LatestPredictionResponse } from "../../lib/api";
 
 export default function CodePage({ params }: { params: { code: string } }) {
@@ -100,14 +101,19 @@ export default function CodePage({ params }: { params: { code: string } }) {
             prev={prev}
             asOf={asOf}
           />
-          <StockChart chart={chart} prediction={prediction} />
+          <div className="grid gap-6 lg:grid-cols-[1fr_280px]">
-          {isIntraday && chart.intraday_status && (
+            <div>
-            <div className="mt-2 text-right text-[11px] text-zinc-500">
+              <StockChart chart={chart} prediction={prediction} />
-              실시간 10분봉 · 60초 갱신 · [{chart.intraday_status}]
+              {isIntraday && chart.intraday_status && (
+                <div className="mt-2 text-right text-[11px] text-zinc-500">
+                  실시간 10분봉 · 60초 갱신 · [{chart.intraday_status}]
+                </div>
+              )}
+              <div className="mt-6">
+                <PredictionPanel code={code} initial={prediction} onResult={setPrediction} />
+              </div>
             </div>
-          )}
+            <SymbolSidebar code={code} />
-          <div className="mt-6">
-            <PredictionPanel code={code} initial={prediction} onResult={setPrediction} />
           </div>
           <div className="mt-6 grid gap-6 md:grid-cols-2">
             <MetricsPanel code={code} />

web/components/SymbolSidebar.tsx

@@ -0,0 +1,117 @@
+"use client";
+
+// 토스증권 우측 정보 사이드바를 흉내낸 카드 묶음.
+//
+// 표시 항목 (백엔드가 안정적으로 제공하는 값으로 한정):
+//   - 오늘: 시가 / 고가 / 저가 / 거래량
+//   - 52주: 최고 / 최저 (1Y 일봉에서 계산)
+//
+// 백엔드에 PER/EPS/시총 데이터가 아직 없으므로 그 항목들은 의도적으로 제외.
+// 차트 폴링과 독립적으로 1Y 일봉을 한 번만 받아 52주 범위만 계산한다.
+
+import { useEffect, useMemo, useState } from "react";
+import { api, type ChartPayload } from "../lib/api";
+
+export function SymbolSidebar({ code }: { code: string }) {
+  const [chart, setChart] = useState<ChartPayload | null>(null);
+  const [err, setErr] = useState<string | null>(null);
+
+  useEffect(() => {
+    let alive = true;
+    setErr(null);
+    setChart(null);
+    api
+      .getChart(code, 365, "1d")
+      .then((c) => {
+        if (alive) setChart(c);
+      })
+      .catch((e) => {
+        if (alive) setErr(e instanceof Error ? e.message : String(e));
+      });
+    return () => {
+      alive = false;
+    };
+  }, [code]);
+
+  const stats = useMemo(() => {
+    if (!chart) return null;
+    const points = chart.ohlcv.filter((p) => p.close != null);
+    if (!points.length) return null;
+    const last = points[points.length - 1];
+
+    let yearHigh = -Infinity;
+    let yearLow = Infinity;
+    for (const p of points) {
+      if (p.high != null && p.high > yearHigh) yearHigh = p.high;
+      if (p.low != null && p.low < yearLow) yearLow = p.low;
+    }
+    return {
+      open: last.open,
+      high: last.high,
+      low: last.low,
+      volume: last.volume,
+      yearHigh: yearHigh === -Infinity ? null : yearHigh,
+      yearLow: yearLow === Infinity ? null : yearLow,
+    };
+  }, [chart]);
+
+  if (err) {
+    return (
+      <div className="rounded-md border border-zinc-800 bg-zinc-900/40 p-4 text-xs text-red-400">
+        시세 정보 로딩 실패: {err}
+      </div>
+    );
+  }
+  if (!stats) {
+    return (
+      <div className="rounded-md border border-zinc-800 bg-zinc-900/40 p-4 text-xs text-zinc-500">
+        시세 정보 로딩 중…
+      </div>
+    );
+  }
+
+  return (
+    <div className="rounded-md border border-zinc-800 bg-zinc-900/40 p-4">
+      <div className="mb-3 text-sm font-medium text-zinc-200">시세 정보</div>
+      <dl className="grid grid-cols-2 gap-y-2 text-sm">
+        <Row label="시가" value={fmt(stats.open)} />
+        <Row label="고가" value={fmt(stats.high)} tone="up" />
+        <Row label="저가" value={fmt(stats.low)} tone="down" />
+        <Row label="거래량" value={fmtCompact(stats.volume)} />
+        <Row label="52주 최고" value={fmt(stats.yearHigh)} tone="up" />
+        <Row label="52주 최저" value={fmt(stats.yearLow)} tone="down" />
+      </dl>
+    </div>
+  );
+}
+
+function Row({
+  label,
+  value,
+  tone,
+}: {
+  label: string;
+  value: string;
+  tone?: "up" | "down";
+}) {
+  const toneCls =
+    tone === "up" ? "text-rose-300" : tone === "down" ? "text-sky-300" : "text-zinc-100";
+  return (
+    <>
+      <dt className="text-zinc-500">{label}</dt>
+      <dd className={`text-right tabular-nums ${toneCls}`}>{value}</dd>
+    </>
+  );
+}
+
+function fmt(n: number | null | undefined): string {
+  if (n == null || !Number.isFinite(n)) return "-";
+  return n.toLocaleString(undefined, { maximumFractionDigits: 0 });
+}
+
+function fmtCompact(n: number | null | undefined): string {
+  if (n == null || !Number.isFinite(n)) return "-";
+  if (n >= 1e8) return `${(n / 1e8).toFixed(1)}억`;
+  if (n >= 1e4) return `${(n / 1e4).toFixed(1)}만`;
+  return n.toLocaleString();
+}