Enhance Notification and User Services with Improved Error Handling and Data Consistency

- Updated GetByID methods in user and customer services to return specific "not found" errors for better clarity in error responses.
- Modified NotificationResponse structure to include a new Recipient field, allowing for more flexible recipient handling.
- Changed CreatedAt and UpdatedAt fields in NotificationResponse to use Unix timestamps (int64) for consistency across the application.
- Improved notification retrieval logic to handle potential nil values for user and customer lookups, ensuring robust data handling.

internal/notification/form.go

@@ -1,7 +1,6 @@
 package notification
 
 import (
-	"time"
 	"tm/pkg/response"
 )
 
@@ -38,6 +37,7 @@ type NotificationListResponse struct {
 type NotificationResponse struct {
 	ID          string            `json:"id"`
 	UserID      string            `json:"user_id"`
+	Recipient   any               `json:"recipient"`
 	Title       string            `json:"title"`
 	Message     string            `json:"message"`
 	Link        *string           `json:"link"`
@@ -49,8 +49,8 @@ type NotificationResponse struct {
 	Methods     map[string]string `json:"methods"`
 	Metadata    map[string]any    `json:"metadata"`
 	ScheduleAt  int64             `json:"schedule_at"`
-	CreatedAt   time.Time         `json:"created_at"`
-	UpdatedAt   time.Time         `json:"updated_at"`
+	CreatedAt   int64             `json:"created_at"`
+	UpdatedAt   int64             `json:"updated_at"`
 	Seen        bool              `json:"seen"`
 	SeenAt      int64             `json:"seen_at"`
 	IsScheduled bool              `json:"is_scheduled"`