2026-07-23 live refresh: 96,712 rows to 2026-07-12, seam contract validated, ablation 6.04/3.10/2.74/2.71

2026-07-19 staged build: 35 columns, observed holidays, complete-day degree days, ERA5T flag, ablation card

Add v1 parquet (96,637 hourly rows, 32 columns)