added migration seeders models and test script

app/Database/Seeds/MarketplaceThemesSeeder.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace App\Database\Seeds;
+
+use CodeIgniter\Database\Seeder;
+
+class MarketplaceThemesSeeder extends Seeder
+{
+    public function run()
+    {
+        $data = [
+            [
+                'id' => '550e8400-e29b-41d4-a716-446655440010',
+                'name' => 'default-light',
+                'display_name' => 'Default Light',
+                'description' => 'Clean and simple light theme',
+                'author' => 'System',
+                'version' => '1.0.0',
+                'thumbnail_url' => null,
+                'download_url' => '/themes/default-light.zip',
+                'price' => 0,
+                'is_published' => true,
+                'metadata' => json_encode(['tags' => ['light', 'clean']]),
+                'created_at' => date('Y-m-d H:i:s'),
+                'updated_at' => date('Y-m-d H:i:s'),
+            ],
+            [
+                'id' => '550e8400-e29b-41d4-a716-446655440011',
+                'name' => 'default-dark',
+                'display_name' => 'Default Dark',
+                'description' => 'Dark theme for night owls',
+                'author' => 'System',
+                'version' => '1.0.0',
+                'thumbnail_url' => null,
+                'download_url' => '/themes/default-dark.zip',
+                'price' => 0,
+                'is_published' => true,
+                'metadata' => json_encode(['tags' => ['dark', 'night']]),
+                'created_at' => date('Y-m-d H:i:s'),
+                'updated_at' => date('Y-m-d H:i:s'),
+            ],
+        ];
+
+        $this->db->table('marketplace_themes')->insertBatch($data);
+    }
+}