feat(backend): expose POST /api/emprunts with departure checklist

eme-backend/src/repositories/materiel.repository.ts

@@ -1,4 +1,4 @@
-import { Prisma } from '@prisma/client';
+import { Materiel, Prisma } from '@prisma/client';
 import { prisma } from '../db/prisma';
 
 export type MaterielAvecCategorie = Prisma.MaterielGetPayload<{ include: { categorie: true } }>;
@@ -35,3 +35,7 @@ export function findDisponiblesParCampus(
     orderBy: { nom: 'asc' },
   });
 }
+
+export function findById(id: number): Promise<Materiel | null> {
+  return prisma.materiel.findUnique({ where: { id } });
+}