added migration seeders models and test script

app/Database/Migrations/2025-01-01-000012_CreateUserAiSettingsTable.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace App\Database\Migrations;
+
+use CodeIgniter\Database\Migration;
+
+class CreateUserAiSettingsTable extends Migration
+{
+    public function up()
+    {
+        $this->forge->addField([
+            'user_id' => [
+                'type' => 'CHAR',
+                'constraint' => 36,
+                'null' => false,
+            ],
+            'default_provider_id' => [
+                'type' => 'CHAR',
+                'constraint' => 36,
+                'null' => true,
+            ],
+            'default_model' => [
+                'type' => 'VARCHAR',
+                'constraint' => 100,
+                'null' => true,
+                'comment' => 'e.g., gpt-4, claude-3-opus',
+            ],
+            'max_tokens' => [
+                'type' => 'INT',
+                'constraint' => 11,
+                'default' => 2048,
+            ],
+            'temperature' => [
+                'type' => 'FLOAT',
+                'default' => 0.7,
+            ],
+            'updated_at' => [
+                'type' => 'DATETIME',
+                'null' => true,
+            ],
+        ]);
+        $this->forge->addPrimaryKey('user_id');
+        $this->forge->addForeignKey('user_id', 'users', 'id', 'CASCADE', 'CASCADE');
+        $this->forge->addForeignKey('default_provider_id', 'ai_providers', 'id', 'SET NULL', 'CASCADE');
+        $this->forge->createTable('user_ai_settings');
+    }
+
+    public function down()
+    {
+        $this->forge->dropTable('user_ai_settings');
+    }
+}