feat(backend): enforce unique names and surface duplicate errors

prisma/migrations/20250930130000_enforce_unique_names/migration.sql

@@ -0,0 +1,16 @@
+-- Drop previous non-unique index to replace it with a unique constraint
+DROP INDEX IF EXISTS "ModelType_category_name_idx";
+
+-- Ensure unique names for machines, components, and pieces
+ALTER TABLE "machines"
+  ADD CONSTRAINT "machines_name_key" UNIQUE ("name");
+
+ALTER TABLE "composants"
+  ADD CONSTRAINT "composants_name_key" UNIQUE ("name");
+
+ALTER TABLE "pieces"
+  ADD CONSTRAINT "pieces_name_key" UNIQUE ("name");
+
+-- Enforce unique category/name pairs for model types (component & piece categories)
+ALTER TABLE "ModelType"
+  ADD CONSTRAINT "ModelType_category_name_key" UNIQUE ("category", "name");