version-2

Date: 2026-09-12. Status: implemented.

Decision. The change ships as 2.0.0. The main table's file keeps its name but its key and row grain change, and the previous table moves to postcode_simd_history.parquet.

Reason. A consumer reading postcode_simd.parquet will get one row per postcode instead of one per life. That is a breaking change and the version must say so.