Add Scope 3 Challenge to Consumption of Energy and Resources

GitHub Issue #1548 - protontypes/open-sustainable-technology Add the Scope 3 Challenge (https://github.com/co3org/Scope3-Challenge) to the Consumption of Energy and Resources section of education.md. The Scope 3 Challenge is a structured open knowledge base on corporate Scope 3 GHG accounting. The current education section covers LCA tools (Brightway, openLCA) and general resource consumption education, but has no resource on corporate GHG accounting -- the framework companies use to measure and manage their supply-chain emissions. The resource covers: - All 15 GHG Protocol Scope 3 categories with worked examples and calculation methods - Root-cause analysis of why supply-chain accounting fails in practice This fits directly at the intersection of energy consumption, resource flows, and corporate climate action.