Changed upsert to INSERT ON CONFLICT DO NOTHING so existing prices are never overwritten. Added unique index on (time_dk, price_area) to enforce no duplicate quarter-hour entries per area. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Changed upsert to INSERT ON CONFLICT DO NOTHING so existing prices are never overwritten. Added unique index on (time_dk, price_area) to enforce no duplicate quarter-hour entries per area. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>