refactor(data/exchanges): 多子类架构 + 工厂入口

- 每个交易所独立子类：BinanceRestClient extends BaseRestClient
- 统一入口 createRestClient(exchangeId) 工厂函数
- KLINE_INTERVAL_MS 移至 constants.ts
- fetchKlines 签名统一为 (symbol, startTime, limit?, endTime?)
- throttle 限流实际生效
- convertBinanceKline interval 参数化
- 删除 filterConsecutive 死代码
- 更新 run/exchange.ts 和 service/bnkline.ts 调用方

data/service/bnkline.ts

@@ -1,7 +1,7 @@
-import { Client } from "../exchanges/rest";
+import { createRestClient } from "../exchanges";
 import type { Kline } from "../types";
 
-const client = new Client("binance");
+const client = createRestClient("binance");
 
 /**
  * 获取 Binance 1m K 线数据（基于 MainClient REST API）。