etl-duckdb

Instructions:

• Run: powershell -ExecutionPolicy Bypass -File .codex/skills/etl-duckdb/scripts/run.ps1
• Output:
  • data/_artifacts/ops.duckdb
  • reports/etl_report.md Fail-safe:
• If inputs missing, produce only the '以묐떒' table in reports/etl_report.md and exit. Evidence Required:
• input_rows, null_cells, duplicated_rows, duckdb_written