- Add shared env loader for migration scripts to load .env and .env.local files at module init
- Add migration script to fix broken delivery note relation fields and backfill missing company data
- Update delivery notes list page: add status filter tabs, company-based collapsible grouping, increased fetch limit, and improved global search
- Add per-item cost price, markup calculations, and total summary rows for cost, selling price, markup, and margin to delivery note detail pages
