Extends import_economics.py from 6-step to 8-step pipeline: - Loads wiki corporation markdown frontmatter as authoritative source - Syncs corporations table (hard error on proper_name divergence per D-182) - Populates corp_presence table (one row per corp × headquarters system) - Splits validation: structural checks block commit; coverage checks post-commit - D-175 Phase 2 gate: 3+ corps per commodity, 1+ corp per system with pop > 100K Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>