fix: gate workspace diagnostic migration

backend/test/workspaces-diagnostics.test.ts

@@ -8,7 +8,7 @@ import type { RuntimeBindings } from "../src/workspaces/runtime-renderer.js";
 import { parseWorkspaceYaml } from "../src/workspaces/schema.js";
 
 const workspace = parseWorkspaceYaml(`workspace:
-  schema_version: 1
+  schema_version: 2
   id: psd-clinical
   name: Policlinico San Donato
   language: it