feat: 引入事件发射器和会话交易量跟踪器，重构策略引擎以支持更灵活的事件处理和交易量计算

src/strategy/common/event-emitter.ts

@@ -0,0 +1,30 @@
+export class StrategyEventEmitter<TEvent extends string, TPayload> {
+  private readonly listeners = new Map<TEvent, Set<(payload: TPayload) => void>>();
+
+  on(event: TEvent, handler: (payload: TPayload) => void): void {
+    const handlers = this.listeners.get(event) ?? new Set<(payload: TPayload) => void>();
+    handlers.add(handler);
+    this.listeners.set(event, handlers);
+  }
+
+  off(event: TEvent, handler: (payload: TPayload) => void): void {
+    const handlers = this.listeners.get(event);
+    if (!handlers) return;
+    handlers.delete(handler);
+    if (handlers.size === 0) {
+      this.listeners.delete(event);
+    }
+  }
+
+  emit(event: TEvent, payload: TPayload, onError?: (error: unknown) => void): void {
+    const handlers = this.listeners.get(event);
+    if (!handlers) return;
+    for (const handler of handlers) {
+      try {
+        handler(payload);
+      } catch (error) {
+        onError?.(error);
+      }
+    }
+  }
+}

src/strategy/common/session-volume.ts

@@ -0,0 +1,28 @@
+import type { PositionSnapshot } from "../../utils/strategy";
+
+export class SessionVolumeTracker {
+  private initialized = false;
+  private previousPositionAmt = 0;
+  private total = 0;
+
+  update(position: PositionSnapshot, referencePrice: number | null): void {
+    if (!this.initialized) {
+      this.previousPositionAmt = position.positionAmt;
+      this.initialized = true;
+      return;
+    }
+    if (referencePrice == null) {
+      this.previousPositionAmt = position.positionAmt;
+      return;
+    }
+    const delta = Math.abs(position.positionAmt - this.previousPositionAmt);
+    if (delta > 0) {
+      this.total += delta * referencePrice;
+    }
+    this.previousPositionAmt = position.positionAmt;
+  }
+
+  get value(): number {
+    return this.total;
+  }
+}

src/strategy/common/subscriptions.ts

@@ -0,0 +1,25 @@
+export type LogHandler = (type: string, detail: string) => void;
+
+interface SubscriptionMessages {
+  subscribeFail: (error: unknown) => string;
+  processFail: (error: unknown) => string;
+}
+
+export function safeSubscribe<T>(
+  subscribe: (cb: (payload: T) => void) => void,
+  handler: (payload: T) => void,
+  log: LogHandler,
+  messages: SubscriptionMessages
+): void {
+  try {
+    subscribe((payload) => {
+      try {
+        handler(payload);
+      } catch (error) {
+        log("error", messages.processFail(error));
+      }
+    });
+  } catch (error) {
+    log("error", messages.subscribeFail(error));
+  }
+}