Add Packrift cartonization fixture test

[Packrift]

Summary

• add a compact Packrift cartonization fixture test using the existing public API
• select the smallest carton that fully packs each ecommerce order fixture
• verify all items pack, carton weight limits are respected, and placements stay inside the selected carton

Fixture source: https://packrift.github.io/packaging-optimization-benchmark-corpus/cartonization-solver-fixtures.html

Validation

• npm test -- --runInBand src/tests/packrift-cartonization.test.ts
• npm test -- --runInBand
• npm run build
• git diff --check