Enhance Notification and User Models with New Fields and Update Swagger Documentation

- Added 'image' and 'link' fields to the NotificationRequest and NotificationResponse structures, improving the flexibility of notification content.
- Updated the 'created_at', 'updated_at', and 'schedule_at' fields to use integer types for Unix timestamps, ensuring consistency in time handling.
- Expanded the tender status enumeration to include 'closed', 'modified', 'suspended', and 'published', enhancing the representation of tender states.
- Reflected these changes in the Swagger documentation, ensuring accurate API specifications for clients.

pkg/notification/entities.go

@@ -33,6 +33,8 @@ type NotificationRequest struct {
 	EventType   EventType           `json:"event_type"`
 	Priority    string              `json:"priority"`
 	ScheduledAt int64               `json:"scheduled_at"`
+	Link        string              `json:"link"`
+	Image       string              `json:"image"`
 	Metadata    map[string]any      `json:"metadata"`
 	Methods     NotificationMethods `json:"methods"`
 }