更新环境配置示例，添加 GRVT 相关的 API 凭证和选项，增强文档以支持新的交易所适配器，确保用户能够正确配置和使用 GRVT 交易功能。

src/exchanges/create-adapter.ts

@@ -0,0 +1,29 @@
+import type { ExchangeAdapter } from "./adapter";
+import { AsterExchangeAdapter, type AsterCredentials } from "./aster-adapter";
+import { GrvtExchangeAdapter, type GrvtCredentials } from "./grvt/adapter";
+
+export interface ExchangeFactoryOptions {
+  symbol: string;
+  exchange?: string;
+  aster?: AsterCredentials;
+  grvt?: GrvtCredentials;
+}
+
+export type SupportedExchangeId = "aster" | "grvt";
+
+export function resolveExchangeId(value?: string | null): SupportedExchangeId {
+  const fallback = (value ?? process.env.EXCHANGE ?? process.env.TRADE_EXCHANGE ?? "aster")
+    .toString()
+    .trim()
+    .toLowerCase();
+  if (fallback === "grvt") return "grvt";
+  return "aster";
+}
+
+export function createExchangeAdapter(options: ExchangeFactoryOptions): ExchangeAdapter {
+  const id = resolveExchangeId(options.exchange);
+  if (id === "grvt") {
+    return new GrvtExchangeAdapter({ ...options.grvt, symbol: options.symbol });
+  }
+  return new AsterExchangeAdapter({ ...options.aster, symbol: options.symbol });
+}