feat: rebuild workspaces as the reference plugin

src/backend/database/db/performance-indexes.ts

@@ -152,11 +152,6 @@ export const PERFORMANCE_INDEXES: PerformanceIndex[] = [
     table: "user_open_tabs",
     columns: "user_id",
   },
-  {
-    name: "idx_user_workspaces_user_id",
-    table: "user_workspaces",
-    columns: "user_id",
-  },
   {
     name: "idx_homepage_items_user_id",
     table: "homepage_items",