UPS API PHP Sample Page

I need a concise, well-commented PHP page that connects to the live UPS API and demonstrates two core capabilities: pulling rates and verifying addresses. The same page should let me submit a sample shipment, retrieve the shipping cost, delivery-time estimate, and the list of available shipping options, then let me enter an address and confirm whether it is valid for both residential and commercial locations.

Please keep everything in plain PHP (7.4+ is fine), using cURL or Guzzle for the requests, and structure the code so I can drop in my own UPS credentials at the top. Error handling has to be clear so I can distinguish authentication problems from bad input.

Deliverables
1. A single, fully commented PHP file that:
• Sends a Rates request and displays cost, transit time, and service list.
• Sends an Address Validation request and shows validation results for residential and commercial addresses.
2. A short README explaining any required PHP extensions, where to place UPS keys, and sample request/response flows.

If anything about the UPS endpoint versions or required request XML/JSON needs clarification, note it in the README rather than hard-coding assumptions. Feel free to add helper functions as long as everything stays in one file for easy testing.