feat(去重逻辑): 增强信号去重机制以区分不同动作

Changes:
* 更新去重键计算逻辑，新增动作字段以区分不同的交易动作（如 REDUCE 和 CLOSE）
* 增加单元测试以验证不同动作在相同价格下的去重行为
* 更新文档以反映去重窗口的变化，确保准确性

internal/subscriber/dedup.go

@@ -37,8 +37,9 @@ func signalKey(source string, data map[string]interface{}) string {
 	symbol := firstNonEmptyField(fieldString(data["symbol"]), fieldString(data["currency"]))
 	period := fieldString(data["period"])
 	direction := strings.ToUpper(firstNonEmptyField(fieldString(data["direction"]), fieldString(data["side"])))
+	action := strings.ToUpper(fieldString(data["action"]))
 	price := fieldString(data["price"])
-	return strings.Join([]string{strings.TrimSpace(source), strategy, symbol, period, direction, price}, "\x1f")
+	return strings.Join([]string{strings.TrimSpace(source), strategy, symbol, period, direction, action, price}, "\x1f")
 }
 
 func firstNonEmptyField(a, b string) string {