Have the MethodDef row owner derive code type, managed kind and the P/Invoke flag for both body decoding and native-boundary inventory. Remove duplicate masks and unreachable fallbacks while preserving raw flags, zero-RVA precedence and ImplMap-specific declaration policy.
Validation: 280 focused source, CLI and MCP tests passed, including cross-workflow flag combinations and declaration/body policy boundaries. Typecheck and lint passed.