Callbacks service docs updated

api/edge/callbacks/internal/model/task.go

@@ -0,0 +1,37 @@
+package model
+
+import (
+	"time"
+
+	"github.com/tech/sendico/pkg/db/storable"
+	"go.mongodb.org/mongo-driver/v2/bson"
+)
+
+// TaskStatus tracks delivery task lifecycle.
+type TaskStatus string
+
+const (
+	TaskStatusPending   TaskStatus = "PENDING"
+	TaskStatusRetry     TaskStatus = "RETRY"
+	TaskStatusDelivered TaskStatus = "DELIVERED"
+	TaskStatusFailed    TaskStatus = "FAILED"
+)
+
+// Task is one callback delivery job.
+type Task struct {
+	storable.Base
+	EventID        string
+	EndpointRef    bson.ObjectID
+	EndpointURL    string
+	SigningMode    string
+	SecretRef      string
+	Headers        map[string]string
+	Payload        []byte
+	Attempt        int
+	MaxAttempts    int
+	MinDelay       time.Duration
+	MaxDelay       time.Duration
+	RequestTimeout time.Duration
+	Status         TaskStatus
+	NextAttemptAt  time.Time
+}