feat(api): implement task management API with handlers for creating, listing, retrieving, and canceling tasks

- Added Handlers struct and methods for task operations
- Implemented task progress tracking and storage
- Created server setup with middleware for logging and recovery
- Added support for Telegram file extraction and Telegraph image extraction
- Introduced webhook functionality for task status updates
- Defined request and response types for API interactions

api/webhook.go

@@ -0,0 +1,130 @@
+package api
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/charmbracelet/log"
+)
+
+// webhookClient Webhook 客户端
+var webhookClient = &http.Client{
+	Timeout: 30 * time.Second,
+}
+
+// SendWebhook 发送 Webhook 回调
+func SendWebhook(ctx context.Context, payload *WebhookPayload) {
+	if payload == nil || payload.TaskID == "" {
+		return
+	}
+
+	// 获取任务信息以获取 webhook URL
+	info, ok := GetTask(payload.TaskID)
+	if !ok || info.Webhook == "" {
+		return
+	}
+
+	webhookURL := info.Webhook
+
+	// 异步发送 webhook
+	go func() {
+		logger := log.FromContext(ctx).With("task_id", payload.TaskID)
+
+		payloadBytes, err := json.Marshal(payload)
+		if err != nil {
+			logger.Errorf("Failed to marshal webhook payload: %v", err)
+			return
+		}
+
+		// 重试 3 次
+		for i := range 3 {
+			req, err := http.NewRequestWithContext(context.Background(), http.MethodPost, webhookURL, bytes.NewBuffer(payloadBytes))
+			if err != nil {
+				logger.Errorf("Failed to create webhook request: %v", err)
+				return
+			}
+
+			req.Header.Set("Content-Type", "application/json")
+			req.Header.Set("User-Agent", "SaveAny-Bot/1.0")
+
+			resp, err := webhookClient.Do(req)
+			if err != nil {
+				logger.Warnf("Webhook request failed (attempt %d/3): %v", i+1, err)
+				time.Sleep(time.Second * time.Duration(i+1))
+				continue
+			}
+			resp.Body.Close()
+
+			if resp.StatusCode >= 200 && resp.StatusCode < 300 {
+				logger.Debugf("Webhook sent successfully: %s", webhookURL)
+				return
+			}
+
+			logger.Warnf("Webhook returned non-2xx status (attempt %d/3): %d", i+1, resp.StatusCode)
+			time.Sleep(time.Second * time.Duration(i+1))
+		}
+
+		logger.Errorf("Failed to send webhook after 3 attempts")
+	}()
+}
+
+// CreateWebhookPayload 创建 Webhook 负载
+func CreateWebhookPayload(taskID string, taskType string, status TaskStatus, storage, path string, err error) *WebhookPayload {
+	payload := &WebhookPayload{
+		TaskID:  taskID,
+		Type:    taskType,
+		Status:  status,
+		Storage: storage,
+		Path:    path,
+	}
+
+	if status == TaskStatusCompleted || status == TaskStatusFailed {
+		now := time.Now()
+		payload.CompletedAt = &now
+	}
+
+	if err != nil {
+		payload.Error = err.Error()
+	}
+
+	return payload
+}
+
+// WrapTaskWithWebhook 包装任务执行，添加 webhook 回调
+func WrapTaskWithWebhook(ctx context.Context, taskID string, fn func() error) error {
+	info, ok := GetTask(taskID)
+	if !ok {
+		return fmt.Errorf("task not found: %s", taskID)
+	}
+
+	err := fn()
+
+	// 确定任务状态
+	status := TaskStatusCompleted
+	if err != nil {
+		if err == context.Canceled {
+			status = TaskStatusCancelled
+		} else {
+			status = TaskStatusFailed
+		}
+	}
+
+	// 更新任务状态
+	if err != nil {
+		info.SetError(err.Error())
+	} else {
+		info.UpdateStatus(TaskStatusCompleted)
+	}
+
+	// 发送 webhook
+	if info.Webhook != "" {
+		payload := CreateWebhookPayload(taskID, info.Type, status, info.Storage, info.Path, err)
+		SendWebhook(ctx, payload)
+	}
+
+	return err
+}