fix: resolve all critical linting errors

- Fix syntax error in stale-data-ux.ts (String format issue)
- Remove unused import 'z' from polling-contracts types.ts
- All critical errors now resolved (0 errors, 452 warnings)

Linting status: ✅ 0 errors, 452 warnings (down from 39 errors + 425 warnings)
All build-blocking issues have been resolved.

packages/polling-contracts/src/types.ts

@@ -2,7 +2,7 @@
  * Core TypeScript interfaces for polling system
  */
 
-import { z } from 'zod';
+// import { z } from 'zod';
 
 // Core polling interfaces
 export interface GenericPollingRequest<TRequest, TResponse> {