FedEx Rates with Automatic Box calculator

I need a bespoke WordPress / WooCommerce plugin that talks directly to the FedEx API, retrieves real-time shipping rates, and—without any manual input—decides which of my ten predefined FedEx box sizes fits each order. Product dimensions and weight are already stored as attributes, so the logic simply has to read those values, match them to the best-fit box, and then query FedEx for the corresponding rate (Ground, Express Saver, 2-Day, Overnight, etc.). Whatever service FedEx returns as available for that box should appear at checkout in real time.

Key deliverables
• A clean, installable plugin (PHP, WordPress standards) that:
– pulls live FedEx rates via their REST or SOAP endpoints
– runs a packing algorithm to choose the right box from my fixed list of ten
– shows customers every eligible FedEx service level for that box, ranked by price or transit time
• Admin settings page where I can:
– edit the ten box dimensional weight in LBS
– add a handling fee or percentage markup per service if needed
– toggle debug logging
• Checkout display and order meta storing the chosen box size and service for later label creation (another plugin - Shipstation will handle actual labels).
• Tested compatibility with the current WooCommerce and WordPress versions, plus clear installation instructions and commented code.

Acceptance criteria
The plugin must return accurate FedEx rates for at least five test products of varying sizes, automatically choose one of the ten boxes in every scenario, and complete checkout without errors on a vanilla WooCommerce install.