feat(views): anonymous daily view counter with social-proof badge

- New table symbol_views_daily(code, view_date, views) via migration 004.
- POST /api/views/{code} UPSERTs and returns today_views; GET returns
  today + last_7d + trend (last 7 days).
- Client dedupes via localStorage (views:logged map keyed by KST date) so a
  given browser counts once per day per code; refresh/extra tabs don't inflate.
- PriceHero shows "오늘 N명이 봤어요" pill when viewsToday > 0.

Read-only social proof — Toss 의 종목 상세에서 익명 카운트로 진입 신호를 주는 패턴.

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

web/app/[code]/page.tsx

@@ -21,6 +21,7 @@ import { SymbolSidebar } from "../../components/SymbolSidebar";
 import { TradingValuePanel } from "../../components/TradingValuePanel";
 import { api, type ChartPayload, type LatestPredictionResponse } from "../../lib/api";
 import { recent } from "../../lib/recent";
+import { shouldRecordView } from "../../lib/views";
 
 export default function CodePage({ params }: { params: { code: string } }) {
   const { code } = params;
@@ -28,6 +29,7 @@ export default function CodePage({ params }: { params: { code: string } }) {
   const [prediction, setPrediction] = useState<LatestPredictionResponse | null>(null);
   const [err, setErr] = useState<string | null>(null);
   const [period, setPeriod] = useState<Period>("3M");
+  const [viewsToday, setViewsToday] = useState<number | null>(null);
 
   const spec = periodSpec(period);
   const isIntraday = spec.interval === "10m";
@@ -37,6 +39,29 @@ export default function CodePage({ params }: { params: { code: string } }) {
     recent.push(code);
   }, [code]);
 
+  // 조회 카운터.
+  //   - 같은 (code, KST today) 는 localStorage 마크로 dedupe → POST 1회.
+  //   - dedupe 실패 (스토리지 잠금 등) 해도 GET 으로 today_views 는 조회.
+  //   - POST 응답이 today_views 를 주므로 별도 GET 안 해도 됨 (한 라운드트립으로 끝).
+  //   - 이미 봤던 종목이면 GET 만.
+  useEffect(() => {
+    let alive = true;
+    const apply = (n: number) => {
+      if (alive) setViewsToday(n);
+    };
+    if (shouldRecordView(code)) {
+      api.recordView(code).then((r) => apply(r.today_views)).catch(() => {
+        // POST 실패 시 GET 한 번 시도 (혹시 다른 사용자 카운트라도 보여줌).
+        api.views(code).then((r) => apply(r.today_views)).catch(() => {});
+      });
+    } else {
+      api.views(code).then((r) => apply(r.today_views)).catch(() => {});
+    }
+    return () => {
+      alive = false;
+    };
+  }, [code]);
+
   useEffect(() => {
     let alive = true;
     setErr(null);
@@ -140,6 +165,7 @@ export default function CodePage({ params }: { params: { code: string } }) {
             prev={prev}
             asOf={asOf}
             series={sparkSeries}
+            viewsToday={viewsToday}
           />
           <div className="grid gap-6 lg:grid-cols-[1fr_280px]">
             <div>