Classify task difficulty from integration boundaries, not ticket titles

For customer-commitment backlogs, classify implementation difficulty from the current acceptance criteria and code surface: Simple means a localized change reusing an existing path; Medium spans several UI/API/query layers but keeps the existing state model; Hard changes verification policy, evidence lineage, authorization, durable analytics, or cross-system delivery guarantees. For partially implemented work, grade the remaining path rather than the original feature. PR line counts are supporting evidence, not the classifier, because generated files and tests can distort size.