The _ProductConstructeurs table was created with wrong column order: - Before: A=product, B=constructeur - After: A=constructeur, B=product (alphabetical order expected by Prisma) This caused Prisma to fail loading constructeurs relations, resulting in empty constructeurs arrays in API responses. Changes: - Added migration to swap A/B columns and recreate foreign keys - Added debug logs in products.service.ts and constructeur-link.util.ts Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>