Implement PostgreSQL history with user isolation

lib/db.js

@@ -0,0 +1,33 @@
+const { Pool } = require('pg');
+const dbConfig = require('./db-config');
+
+const pool = new Pool(dbConfig);
+
+async function initSchema() {
+  const client = await pool.connect();
+  try {
+    const query = `
+      CREATE TABLE IF NOT EXISTS test_results (
+        id UUID PRIMARY KEY,
+        url TEXT NOT NULL,
+        timestamp TIMESTAMPTZ NOT NULL,
+        is_mobile BOOLEAN NOT NULL,
+        scores JSONB NOT NULL,
+        metrics JSONB NOT NULL,
+        user_uuid TEXT NOT NULL,
+        user_ip TEXT NOT NULL
+      );
+    `;
+    await client.query(query);
+    console.log("Schema initialized: test_results table ready.");
+  } catch (err) {
+    console.error("Error initializing schema:", err);
+  } finally {
+    client.release();
+  }
+}
+
+module.exports = {
+  pool,
+  initSchema
+};