fix backend CORS: add global CORS filter and catch-all OPTIONS route; fix MySQL insert errors: set updatedField to empty string instead of null in models without updated_at column

app/Config/Filters.php

@@ -73,6 +73,7 @@ class Filters extends BaseFilters
      */
     public array $globals = [
         'before' => [
+            'cors',
             // 'honeypot',
             // 'csrf',
             // 'invalidchars',

app/Config/Routes.php

@@ -11,6 +11,15 @@ $routes->get('/', 'Home::index');
 // API Routes - Version 1.0
 // ============================================================================
 
+// Catch-all CORS preflight handler for all API routes
+$routes->options('api/v1/(:any)', function () {
+    $response = service('response');
+    return $response->setStatusCode(200)
+        ->setHeader('Access-Control-Allow-Origin', '*')
+        ->setHeader('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS')
+        ->setHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization, X-API-Key');
+});
+
 // Public endpoints (no authentication required)
 $routes->group('api/v1', ['namespace' => 'App\Controllers\Api\V1', 'filter' => 'cors'], function ($routes) {
     // Authentication

app/Models/ActivityLogModel.php

@@ -25,7 +25,7 @@ class ActivityLogModel extends Model
 
     protected $useTimestamps = true;
     protected $createdField = 'created_at';
-    protected $updatedField = null;
+    protected $updatedField = '';
 
     protected $validationRules = [
         'action' => 'required|max_length[255]',

app/Models/AiMessageModel.php

@@ -22,7 +22,7 @@ class AiMessageModel extends Model
 
     protected $useTimestamps = true;
     protected $createdField = 'created_at';
-    protected $updatedField = null;
+    protected $updatedField = '';
 
     protected $validationRules = [
         'chat_id' => 'required',

app/Models/AiProviderModel.php

@@ -22,7 +22,7 @@ class AiProviderModel extends Model
 
     protected $useTimestamps = true;
     protected $createdField = 'created_at';
-    protected $updatedField = null;
+    protected $updatedField = '';
 
     protected $validationRules = [
         'name' => 'required|max_length[100]|is_unique[ai_providers.name]',

app/Models/ApiAuthKeyModel.php

@@ -27,7 +27,7 @@ class ApiAuthKeyModel extends Model
 
     protected $useTimestamps = false;
     protected $createdField = 'created_at';
-    protected $updatedField = null;
+    protected $updatedField = '';
 
     protected $validationRules = [
         'user_id' => 'required',

app/Models/CategoryModel.php

@@ -22,7 +22,7 @@ class CategoryModel extends Model
 
     protected $useTimestamps = true;
     protected $createdField = 'created_at';
-    protected $updatedField = null;
+    protected $updatedField = '';
 
     protected $validationRules = [
         'user_id' => 'required',

app/Models/ProjectModel.php

@@ -22,7 +22,7 @@ class ProjectModel extends Model
 
     protected $useTimestamps = true;
     protected $createdField = 'created_at';
-    protected $updatedField = null;
+    protected $updatedField = '';
 
     protected $validationRules = [
         'user_id' => 'required',