以下是整合了所有改进点的完整代码实现：

package main

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"log"
	"net/http"
	"sync"
	"time"

	"github.com/go-redis/redis/v8"
	"github.com/robfig/cron/v3"
	"golang.org/x/time/rate"
)

// 任务状态常量
const (
	StatusReady    = "就绪"
	StatusRunning  = "运行中"
	StatusStopped  = "已停止"
	StatusDisabled = "已禁用"
)

// 任务类型常量
const (
	TaskTypePeriodic = "periodic" // 周期性任务
	TaskTypeOneShot  = "oneshot"  // 一次性任务
)

// API调用结果结构
type APIResult struct {
	StatusCode int           // HTTP状态码
	Body       string        // 响应体
	Error      error         // 错误信息
	Duration   time.Duration // 耗时
	Retries