Refactor Customer and User Repository Methods for ObjectID Handling

- Updated GetByIDs methods in customer and user repositories to convert string IDs to bson.ObjectID, ensuring proper handling of MongoDB object IDs.
- Enhanced error handling for ID conversion to provide clearer feedback when invalid IDs are provided.
- Modified notification service calls in customer and user services to use context.Background() for asynchronous email sending, improving concurrency management.
- Ensured consistent handling of company IDs in the customer repository for retrieving customers by companies.

internal/customer/service.go

@@ -152,7 +152,7 @@ func (s *customerService) Register(ctx context.Context, form *CreateCustomerForm
 		"company_ids": Companies,
 	})
 
-	s.notification.SendEmail(ctx, notification.Model{
+	go s.notification.SendEmail(context.Background(), notification.Model{
 		Recipient: customer.Email,
 		Title:     "Welcome to Opplens",
 		Message:   fmt.Sprintf("Welcome to Opplens\nUsername: %s\nPassword: %s", strings.ToLower(customer.Username), form.Password),
@@ -428,7 +428,7 @@ func (s *customerService) UpdateStatus(ctx context.Context, id string, form *Upd
 		"status":      form.Status,
 	})
 
-	s.notification.SendEmail(ctx, notification.Model{
+	go s.notification.SendEmail(context.Background(), notification.Model{
 		Recipient: customer.Email,
 		Title:     "Account Status Updated",
 		Message:   fmt.Sprintf("Your account has been %s", strings.ToUpper(form.Status)),
@@ -888,7 +888,7 @@ func (s *customerService) RequestResetPassword(ctx context.Context, form *Reques
 	}
 
 	// Send OTP via email
-	s.notification.SendEmail(ctx, notification.Model{
+	go s.notification.SendEmail(context.Background(), notification.Model{
 		Recipient: form.Email,
 		Title:     "Password Reset",
 		Message:   fmt.Sprintf("Your password reset code is: %s", otpCode),
@@ -1083,7 +1083,7 @@ func (s *customerService) ResetPassword(ctx context.Context, form *ResetPassword
 		"customer_id": customer.ID,
 	})
 
-	s.notification.SendEmail(ctx, notification.Model{
+	go s.notification.SendEmail(context.Background(), notification.Model{
 		Recipient: tokenData.Email,
 		Title:     "Password Reset Success",
 		Message:   "Your password has been reset successfully",