feat: create DatabaseService to handle driver management and schema discovery operations

backend/app/Services/DatabaseService.php

@@ -0,0 +1,77 @@
+<?php
+
+namespace App\Services;
+
+use App\Contracts\DatabaseDriverInterface;
+use App\Contracts\SchemaDiscoveryInterface;
+
+class DatabaseService
+{
+    protected ?DatabaseDriverInterface $driver = null;
+
+    /**
+     * Set the database driver.
+     */
+    public function setDriver(DatabaseDriverInterface $driver): self
+    {
+        $this->driver = $driver;
+        return $this;
+    }
+
+    /**
+     * Get the current driver.
+     * 
+     * @throws \Exception
+     */
+    public function getDriver(): DatabaseDriverInterface
+    {
+        if (!$this->driver) {
+            throw new \Exception("Database driver not initialized.");
+        }
+        return $this->driver;
+    }
+
+    /**
+     * Establish a connection.
+     */
+    public function connect(array $config): bool
+    {
+        return $this->getDriver()->connect($config);
+    }
+
+    /**
+     * Get all databases.
+     */
+    public function getDatabases(): array
+    {
+        $driver = $this->getDriver();
+        if ($driver instanceof SchemaDiscoveryInterface) {
+            return $driver->getDatabases();
+        }
+        throw new \Exception("Driver does not support schema discovery.");
+    }
+
+    /**
+     * Get all tables.
+     */
+    public function getTables(): array
+    {
+        $driver = $this->getDriver();
+        if ($driver instanceof SchemaDiscoveryInterface) {
+            return $driver->getTables();
+        }
+        throw new \Exception("Driver does not support schema discovery.");
+    }
+
+    /**
+     * Get table schema.
+     */
+    public function getTableSchema(string $table): array
+    {
+        $driver = $this->getDriver();
+        if ($driver instanceof SchemaDiscoveryInterface) {
+            return $driver->getTableSchema($table);
+        }
+        throw new \Exception("Driver does not support schema discovery.");
+    }
+}