Remove obsolete customer endpoint and update related documentation

- Deleted the `/admin/v1/customers/{id}/with-companies` endpoint from the API documentation and Swagger files to streamline the API structure.
- Updated the router to remove the corresponding route registration for the deprecated endpoint.
- Enhanced the company repository and service to support batch retrieval of companies by IDs, improving efficiency in data handling.
- Adjusted customer service methods to utilize the new batch retrieval functionality for loading companies associated with customers.
- Improved logging practices to provide better traceability for company retrieval operations.

internal/customer/service.go

@@ -1280,24 +1280,35 @@ func (s *customerService) getDefaultTimezone(timezone *string) string {
 
 // loadCompaniesForCustomer loads company summaries for a customer
 func (s *customerService) loadCompaniesForCustomer(ctx context.Context, customer *Customer) ([]*CompanySummary, error) {
-	var companies []*CompanySummary
+	if len(customer.CompanyIDs) == 0 {
+		return []*CompanySummary{}, nil
+	}
 
-	// Load companies from CompanyIDs
-	for _, companyID := range customer.CompanyIDs {
-		company, err := s.companyService.GetCompanyByID(ctx, companyID)
-		if err != nil {
-			s.logger.Warn("Failed to load company for customer", map[string]interface{}{
-				"error":       err.Error(),
-				"customer_id": customer.ID,
-				"company_id":  companyID,
-			})
-			continue // Skip companies that can't be loaded
-		}
-		companies = append(companies, &CompanySummary{
+	// Load companies in batch using the new GetCompaniesByIDs method
+	companies, err := s.companyService.GetCompaniesByIDs(ctx, customer.CompanyIDs)
+	if err != nil {
+		s.logger.Error("Failed to load companies for customer", map[string]interface{}{
+			"error":       err.Error(),
+			"customer_id": customer.ID,
+			"company_ids": customer.CompanyIDs,
+		})
+		return []*CompanySummary{}, err
+	}
+
+	// Convert to CompanySummary format
+	var companySummaries []*CompanySummary
+	for _, company := range companies {
+		companySummaries = append(companySummaries, &CompanySummary{
 			ID:   company.ID.Hex(),
 			Name: company.Name,
 		})
 	}
 
-	return companies, nil
+	s.logger.Info("Companies loaded for customer", map[string]interface{}{
+		"customer_id":     customer.ID,
+		"requested_count": len(customer.CompanyIDs),
+		"loaded_count":    len(companySummaries),
+	})
+
+	return companySummaries, nil
 }