need to do R&D on the existing FedEx shipping, tracking, and webhook implementation across `evergreen_pos_be`, `evergreen_pos_fe`, and `evergreenpos_E-commerce_new`.
- Do R&D on the existing FedEx shipping, tracking, and webhook implementation across `evergreen_pos_be`, `evergreen_pos_fe`, and `evergreenpos_E-commerce_new`. - Analyze FedEx sandbox capabilities and verify whether shipment tracking events such as SHIPPED, IN_TRANSIT, OUT_FOR_DELIVERY, and DELIVERED can be simulated during testing. - Investigate how to configure and test FedEx webhooks through the Developer Portal, including webhook project creation, callback URL, security token, and the “TRY THIS WEBHOOK” feature. - Verify sandbox and account eligibility for Advanced Integrated Visibility webhooks, including any restrictions for our FedEx account. - Check the existing backend webhook handler, event validation, tracking status updates, tracking history, estimated delivery updates, and duplicate-event handling. - Verify email notifications for each tracking event and research how to test notifications when FedEx sandbox does not generate actual tracking updates. - Prepare an R&D report with existing code paths, configuration requirements, testing steps, limitations, gaps, and recommendations. Do not modify production data or implement code changes during the initial R&D phase.