added migration seeders models and test script

app/Database/Migrations/2025-01-01-000010_CreateAiProvidersTable.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace App\Database\Migrations;
+
+use CodeIgniter\Database\Migration;
+
+class CreateAiProvidersTable extends Migration
+{
+    public function up()
+    {
+        $this->forge->addField([
+            'id' => [
+                'type' => 'CHAR',
+                'constraint' => 36,
+                'null' => false,
+            ],
+            'name' => [
+                'type' => 'VARCHAR',
+                'constraint' => 100,
+                'null' => false,
+                'comment' => 'openai, anthropic, google, etc.',
+            ],
+            'display_name' => [
+                'type' => 'VARCHAR',
+                'constraint' => 255,
+                'null' => false,
+            ],
+            'base_url' => [
+                'type' => 'TEXT',
+                'null' => true,
+                'comment' => 'Override endpoint',
+            ],
+            'is_builtin' => [
+                'type' => 'BOOLEAN',
+                'default' => true,
+                'comment' => 'False for user-added custom providers',
+            ],
+            'created_at' => [
+                'type' => 'DATETIME',
+                'null' => true,
+            ],
+        ]);
+        $this->forge->addKey('id', true);
+        $this->forge->addUniqueKey('name');
+        $this->forge->createTable('ai_providers');
+    }
+
+    public function down()
+    {
+        $this->forge->dropTable('ai_providers');
+    }
+}