Docs: Quick start PostgreSQL migration

Ajout des outils de migration et documentation:
- scripts/verify-postgres-connection.js: Test connexion PostgreSQL
- scripts/run-migration.sh: Script automatique de migration
- docker-compose.yml: Volume mount pour accès SQLite depuis container
- MIGRATION-STEPS.md: Guide pas-à-pas complet de migration

La migration peut maintenant être lancée avec:
  docker-compose build notes-app
  docker-compose up -d
  bash scripts/run-migration.sh

scripts/verify-postgres-connection.js

@@ -0,0 +1,44 @@
+const { Pool } = require('pg');
+
+const DATABASE_URL = process.env.DATABASE_URL || 'postgresql://noteflow:noteflow_secure_password_change_me@postgres:5499/noteflow';
+
+async function verifyConnection() {
+  const pool = new Pool({
+    connectionString: DATABASE_URL,
+    max: 1,
+    connectionTimeoutMillis: 5000,
+  });
+
+  try {
+    console.log('🔍 Test de connexion PostgreSQL...');
+    console.log('📍 URL:', DATABASE_URL.replace(/:[^:@]+@/, ':***@'));
+
+    const client = await pool.connect();
+    console.log('✅ Connexion PostgreSQL réussie!');
+
+    // Vérifier les tables existantes
+    const tables = await client.query(`
+      SELECT tablename FROM pg_tables
+      WHERE schemaname = 'public'
+      ORDER BY tablename
+    `);
+
+    console.log('\n📋 Tables existantes:', tables.rows.length);
+    tables.rows.forEach(row => console.log('  -', row.tablename));
+
+    // Vérifier les articles RSS si la table existe
+    if (tables.rows.some(r => r.tablename === 'rss_articles')) {
+      const count = await client.query('SELECT COUNT(*) FROM rss_articles');
+      console.log('\n📰 Articles RSS:', count.rows[0].count);
+    }
+
+    client.release();
+    await pool.end();
+
+  } catch (error) {
+    console.error('❌ Erreur:', error.message);
+    process.exit(1);
+  }
+}
+
+verifyConnection();