feat: export feature group zod schema/type

Author: gregnr

packages/mcp-server-supabase/src/index.ts

@@ -1,2 +1,6 @@
 export type { SupabasePlatform } from './platform/index.js';
-export * from './server.js';
+export {
+  createSupabaseMcpServer,
+  type SupabaseMcpServerOptions,
+} from './server.js';
+export { featureGroupSchema, type FeatureGroup } from './types.js';