Add strict types and type hints across API

Apply strict_types and extensive type declarations throughout the API and models, improving type safety and error handling. Key changes: add declare(strict_types=1) to many files; convert properties, method parameters and return values to typed signatures (PDO, arrays, ints, strings, bools, nullables); switch exception handling to Throwable in index and Router; improve Router, controllers and model method signatures and nullability handling; refine file/image serving security checks and headers in ImageController; strengthen Database typing and initialization methods; return explicit types from BaseModel CRUD helpers and counting; update Media/Cast/Adult/Game/Console/Settings controllers and models to use typed methods, better validation, and clearer update/create return types. Also add AGENTS.md (agent skills index), update README with Swagger/OpenAPI usage instructions, and add /.windsurf to .gitignore. These changes aim to harden runtime correctness, make intended contracts explicit, and prepare the codebase for easier maintenance and static analysis.

api/models/Settings.php

@@ -1,19 +1,21 @@
 <?php
 
+declare(strict_types=1);
+
 require_once __DIR__ . '/BaseModel.php';
 
 class Settings extends BaseModel {
-    protected $table = 'settings';
-    
-    public function __construct($pdo) {
+    protected string $table = 'settings';
+
+    public function __construct(PDO $pdo) {
         parent::__construct($pdo);
     }
-    
-    public function getSettings() {
+
+    public function getSettings(): ?array {
         $stmt = $this->pdo->prepare("SELECT * FROM {$this->table} WHERE id = 1");
         $stmt->execute();
         $settings = $stmt->fetch();
-        
+
         if ($settings) {
             // Decode enabled_categories from JSON
             $settings['enabled_categories'] = $settings['enabled_categories'] ? json_decode($settings['enabled_categories'], true) : [];
@@ -21,11 +23,11 @@ class Settings extends BaseModel {
             $settings['show_adult_content'] = (bool)$settings['show_adult_content'];
             $settings['auto_play_trailers'] = (bool)$settings['auto_play_trailers'];
         }
-        
+
         return $settings;
     }
-    
-    public function updateSettings($data) {
+
+    public function updateSettings(array $data): ?array {
         $updateData = [];
         
         if (isset($data['enabled_categories']) && is_array($data['enabled_categories'])) {