feat: add DatabaseDriverInterface to define base database operations

backend/app/Contracts/DatabaseDriverInterface.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace App\Contracts;
+
+interface DatabaseDriverInterface
+{
+    /**
+     * Set the connection parameters and establish a connection.
+     */
+    public function connect(array $config): bool;
+
+    /**
+     * Execute a raw query.
+     */
+    public function query(string $sql, array $bindings = []): array;
+
+    /**
+     * Get the underlying connection instance.
+     */
+    public function getConnection();
+}