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/database.ts

@@ -0,0 +1,33 @@
+import { Pool } from "pg";
+
+// Configuration de la base de données
+const dbConfig = {
+  host: process.env.DB_HOST || "localhost",
+  port: parseInt(process.env.DB_PORT || "5432"),
+  database: process.env.DB_NAME || "peakskills",
+  user: process.env.DB_USER || "peakskills_user",
+  password: process.env.DB_PASSWORD || "peakskills_password",
+};
+
+// Pool de connexions global
+let pool: Pool | null = null;
+
+export function getPool(): Pool {
+  if (!pool) {
+    pool = new Pool(dbConfig);
+
+    pool.on("error", (err) => {
+      console.error("Unexpected error on idle client", err);
+      process.exit(-1);
+    });
+  }
+
+  return pool;
+}
+
+export async function closePool(): Promise<void> {
+  if (pool) {
+    await pool.end();
+    pool = null;
+  }
+}