Add super admin user management

backend/db.js

@@ -85,6 +85,26 @@ const initDB = async () => {
             );
         `);
 
+        await pool.query(`
+            CREATE TABLE IF NOT EXISTS app_users (
+                id SERIAL PRIMARY KEY,
+                name VARCHAR(255) NOT NULL,
+                email VARCHAR(255) NOT NULL UNIQUE,
+                password_hash TEXT NOT NULL,
+                is_active BOOLEAN DEFAULT TRUE,
+                created_at TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP,
+                updated_at TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP
+            );
+        `);
+
+        await pool.query(`
+            ALTER TABLE app_users
+            ALTER COLUMN created_at TYPE TIMESTAMPTZ USING created_at AT TIME ZONE 'America/Sao_Paulo',
+            ALTER COLUMN created_at SET DEFAULT CURRENT_TIMESTAMP,
+            ALTER COLUMN updated_at TYPE TIMESTAMPTZ USING updated_at AT TIME ZONE 'America/Sao_Paulo',
+            ALTER COLUMN updated_at SET DEFAULT CURRENT_TIMESTAMP;
+        `).catch(() => {});
+
         await pool.query(`
             ALTER TABLE stock_campaign_queue
             ALTER COLUMN created_at TYPE TIMESTAMPTZ USING created_at AT TIME ZONE 'America/Sao_Paulo',
@@ -122,6 +142,7 @@ const initDB = async () => {
         await pool.query(`CREATE INDEX IF NOT EXISTS idx_orders_cliente_fone ON orders (cliente_fone);`);
         await pool.query(`CREATE INDEX IF NOT EXISTS idx_orders_produto_id ON orders (produto_id);`);
         await pool.query(`CREATE INDEX IF NOT EXISTS idx_orders_data_pedido_date ON orders (data_pedido_date);`);
+        await pool.query(`CREATE INDEX IF NOT EXISTS idx_app_users_email ON app_users (LOWER(email));`);
 
         console.log('Database initialized successfully.');
     } catch (err) {