feat: add PostgreSQL database support and development scripts

- Added pg and @types/pg dependencies for PostgreSQL integration
- Created database testing and backend initialization scripts
- Changed dev server port to 3002 to avoid conflicts

scripts/test-db.js

@@ -0,0 +1,25 @@
+#!/usr/bin/env node
+
+// Database connection test script
+const { testConnection } = require('../src/lib/database/config');
+
+async function testDatabaseConnection() {
+  console.log('🔗 Testing database connection...');
+  
+  try {
+    const success = await testConnection();
+    
+    if (success) {
+      console.log('✅ Database connection successful!');
+      process.exit(0);
+    } else {
+      console.log('❌ Database connection failed!');
+      process.exit(1);
+    }
+  } catch (error) {
+    console.error('❌ Database connection error:', error.message);
+    process.exit(1);
+  }
+}
+
+testDatabaseConnection();