docs: add JSDoc comment to ListDatabasesOutput type to clarify public usage for UI components

Author: tsck

src/tools/mongodb/metadata/listDatabases.ts

@@ -15,6 +15,8 @@ export const ListDatabasesOutputSchema = {
     totalCount: z.number(),
 };
 
+// JSDoc comment needed to tell knip that this is intentionally public
+/** @public - Used by UI components */
 export type ListDatabasesOutput = z.infer<z.ZodObject<typeof ListDatabasesOutputSchema>>;
 
 export class ListDatabasesTool extends MongoDBToolBase {