StockTrade 컴포넌트 훅 분리 (Phase 4): 2,788→1,932줄

8개 커스텀 훅으로 state/handler 로직 추출:
- usePortfolio: 포트폴리오 CRUD, 예수금, 브로커 그룹
- useSellHistory: 매도 내역 CRUD, 드로어/폼 상태
- useAiCoach: AI 코치 분석 + 캐시
- useAssetHistory: 자산 추이 차트 데이터
- useMarketContext: VIX/F&G/국채/WTI 시장 데이터
- useAiBalance: AI 모의투자 잔고, 수동 주문
- useReportData: 리포트 정렬, 차트, 집중도 분석
- useAdvisor: 어드바이저 프롬프트 빌더

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/pages/stock/stockUtils.js

@@ -0,0 +1,125 @@
+/* ── helpers ─────────────────────────────────────────────────────── */
+
+export const formatNumber = (value) => {
+    if (value === null || value === undefined || value === '') return '-';
+    const numeric = Number(value);
+    if (Number.isNaN(numeric)) return value;
+    return new Intl.NumberFormat('ko-KR').format(numeric);
+};
+
+export const formatPercent = (value) => {
+    if (value === null || value === undefined || value === '') return '-';
+    if (typeof value === 'string' && value.includes('%')) return value;
+    const numeric = Number(value);
+    if (Number.isNaN(numeric)) return value;
+    return `${numeric >= 0 ? '+' : ''}${numeric.toFixed(2)}%`;
+};
+
+export const pickFirst = (...values) =>
+    values.find((value) => value !== undefined && value !== null && value !== '');
+
+export const getQty = (item) =>
+    pickFirst(item?.qty, item?.quantity, item?.holding, item?.hold_qty);
+
+export const getBuyPrice = (item) =>
+    pickFirst(
+        item?.buy_price,
+        item?.avg_price,
+        item?.avg,
+        item?.purchase_price,
+        item?.buyPrice,
+        item?.price
+    );
+
+export const getCurrentPrice = (item) =>
+    pickFirst(
+        item?.current_price,
+        item?.current,
+        item?.cur_price,
+        item?.now_price,
+        item?.market_price
+    );
+
+export const getProfitRate = (item) =>
+    pickFirst(
+        item?.profit_rate,
+        item?.profitRate,
+        item?.profit_pct,
+        item?.profitPercent,
+        item?.pnl_rate,
+        item?.return_rate,
+        item?.yield
+    );
+
+export const getProfitLoss = (item) =>
+    pickFirst(item?.profit_loss, item?.pnl, item?.profitLoss);
+
+export const toNumeric = (value) => {
+    if (value === null || value === undefined || value === '') return null;
+    const numeric = Number(String(value).replace(/[^0-9.-]/g, ''));
+    return Number.isNaN(numeric) ? null : numeric;
+};
+
+/* ── Chart colors ──────────────────────────────────────────────── */
+
+export const CHART_COLORS = ['#818cf8', '#fbbf24', '#34d399', '#f472b6', '#fb923c', '#a78bfa', '#38bdf8', '#4ade80'];
+
+export const profitColorClass = (numericValue) => {
+    if (numericValue > 0) return 'is-up';
+    if (numericValue < 0) return 'is-down';
+    if (numericValue === 0) return 'is-flat';
+    return '';
+};
+
+export const getVixLabel = (vix) => {
+    if (vix < 12) return '극히 낮음 (안일 주의)';
+    if (vix < 20) return '정상 (안정적)';
+    if (vix < 30) return '주의 (불확실성 증가)';
+    if (vix < 40) return '높음 (극도의 공포)';
+    return '극단 (패닉)';
+};
+
+export const getFgLabel = (score) => {
+    if (score <= 25) return '극단적 공포';
+    if (score <= 45) return '공포';
+    if (score <= 55) return '중립';
+    if (score <= 75) return '탐욕';
+    return '극단적 탐욕';
+};
+
+/* ── empty portfolio form ────────────────────────────────────────── */
+
+export const emptyPortfolioForm = {
+    broker: '',
+    ticker: '',
+    name: '',
+    quantity: '',
+    avg_price: '',
+};
+
+/* ── empty sell-history form ─────────────────────────────────────── */
+
+export const toLocalDatetimeValue = (isoStr) => {
+    if (!isoStr) return '';
+    const d = new Date(isoStr);
+    const pad = (n) => String(n).padStart(2, '0');
+    return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())}T${pad(d.getHours())}:${pad(d.getMinutes())}`;
+};
+
+export const emptySellForm = () => ({
+    broker: '',
+    ticker: '',
+    name: '',
+    quantity: '',
+    avg_price: '',
+    sell_price: '',
+    commission: '',
+    sold_at: toLocalDatetimeValue(new Date().toISOString()),
+});
+
+/* ── TAB IDs ─────────────────────────────────────────────────────── */
+
+export const TAB_PORTFOLIO = 'portfolio';
+export const TAB_AI = 'ai';
+export const TAB_REPORT = 'report';
+export const TAB_ADVISOR = 'advisor';