feat(web): K线图库对比 —— TradingView Lightweight Charts 实现 + 双库切换

- 按确认方案「两套实现并存对比」：
  - npm 依赖 lightweight-charts@4.2.3（v3 §21 推荐库）
  - components/StockChart/chartTypes.ts：共享 props 接口
  - CandleChart.tsx（ECharts 版，重构复用共享类型）+ CandleChartLW.tsx
    （Lightweight 版：蜡烛+成交量副刻度+MA+成交实心箭头/未成交信号圆点 markers）
  - StockChart.tsx wrapper；个股页顶部「ECharts / Lightweight」切换（默认 Lightweight）
- /stocks/600519.SH 冒烟 200；tsc --noEmit 通过

frontend/web/components/StockChart/CandleChart.tsx

@@ -8,7 +8,8 @@
  * - signals（未成交意图）：空心标记 —— signal_buy 红圈 ▲ / signal_sell 绿圈
  * 组件只做展示，绝不自行计算（数据来自后端 Chart API）。
  *
- * 基于 ECharts candlestick；组件层隔离，便于后续替换 TradingView Lightweight Charts。
+ * 基于 ECharts candlestick（ECharts 实现）；另一套实现见 CandleChartLW.tsx（TradingView
+ * Lightweight Charts），两套共用同一 props 接口（chartTypes.ts）供对比。
  */
 import { useEffect, useRef } from "react";
 import * as echarts from "echarts/core";
@@ -16,6 +17,8 @@ import { BarChart, CandlestickChart, LineChart, ScatterChart } from "echarts/cha
 import { GridComponent, TooltipComponent } from "echarts/components";
 import { CanvasRenderer } from "echarts/renderers";
 import type { ChartMarker } from "@/lib/types";
+import type { CandleChartProps } from "./chartTypes";
+export type { CandleDatum } from "./chartTypes";
 
 echarts.use([
   CandlestickChart,
@@ -38,31 +41,15 @@ const C = {
   ma60: "#d4a72c",
 };
 
-export interface CandleDatum {
-  time: string;
-  open: number;
-  close: number;
-  low: number;
-  high: number;
-}
-
 export function CandleChart({
   data,
-  volume,
+  volume = [],
   indicators = {},
   fills = [],
   signals = [],
   height = 480,
   name = "",
-}: {
-  data: CandleDatum[];
-  volume?: { time: string; value: number | null }[];
-  indicators?: Record<string, { time: string; value: number | null }[]>;
-  fills?: ChartMarker[];
-  signals?: ChartMarker[];
-  height?: number;
-  name?: string;
-}) {
+}: CandleChartProps) {
   const ref = useRef<HTMLDivElement>(null);
 
   useEffect(() => {