ron86i/go-siat ? reverse-engineered prompt

Build me a Go SDK for integrating with Bolivia’s SIAT tax system, with a clean and friendly API that hides the messy SOAP and XML details from the user. I want to be able to create a client with basic config, then call simple methods for things like verifying a NIT, getting CUIS and CUFD codes, syncing catalogs, registering and closing POS sessions, and sending invoices and adjustment documents. It should handle digital signatures for the electronic invoicing flow, plus compression and encoding of invoice packages where needed. Please make it type safe, organized by service, and easy to use with builder style request objects instead of raw XML. Include good error handling, context support with timeouts, and some examples or tests that show the main flows working. If you need to check the current SIAT docs online while building it, do that too.