feat: add PostgreSQL support and enhance evaluation loading

- Added `pg` and `@types/pg` dependencies for PostgreSQL integration.
- Updated `useEvaluation` hook to load user evaluations from the API, improving data management.
- Refactored `saveUserEvaluation` and `loadUserEvaluation` functions to interact with the API instead of localStorage.
- Introduced error handling for profile loading and evaluation saving to enhance robustness.
- Added new methods for managing user profiles and evaluations, including `clearUserProfile` and `loadEvaluationForProfile`.

services/index.ts

@@ -0,0 +1,12 @@
+// Server-side services (Node.js only)
+// Note: These exports are only for server-side usage (API routes)
+// Don't import from this index in client-side code to avoid bundling server dependencies
+
+// Database services (server-only)
+export { getPool, closePool } from "./database";
+
+// Evaluation services (server-only)
+export { EvaluationService, evaluationService } from "./evaluation-service";
+
+// API client (can be used client-side)
+export { ApiClient, apiClient } from "./api-client";