fix(ErrorBoundaries): use Environment class instead of direct $_ENV access

Replace direct $_ENV/$_SERVER access with framework's Environment class
to follow proper framework patterns and enable Docker Secrets support.

Changes:
- Add Environment and EnvKey imports
- Use $container->get(Environment::class) for environment access
- Replace $_ENV['APP_ENV'] with $env->getString(EnvKey::APP_ENV, ...)
- Rename internal method to registerServices for clarity
- Add documentation explaining the pattern

Co-Authored-By: Claude <noreply@anthropic.com>

src/Framework/ErrorBoundaries/Middleware/MiddlewareServiceProvider.php

@@ -4,6 +4,8 @@ declare(strict_types=1);
 
 namespace App\Framework\ErrorBoundaries\Middleware;
 
+use App\Framework\Config\Environment;
+use App\Framework\Config\EnvKey;
 use App\Framework\DI\Container;
 use App\Framework\DI\Initializer;
 use App\Framework\ErrorBoundaries\ErrorBoundaryFactory;
@@ -12,6 +14,11 @@ use App\Framework\Logging\Logger;
 
 /**
  * Service provider for error boundary middleware
+ *
+ * Note: The #[Initializer] method uses the Container to get Environment,
+ * following framework patterns for environment-aware configuration.
+ * For manual/custom configuration, use the factory methods:
+ * development(), production(), apiOnly(), or custom().
  */
 final readonly class MiddlewareServiceProvider
 {
@@ -20,8 +27,34 @@ final readonly class MiddlewareServiceProvider
     ) {
     }
 
+    /**
+     * Initializer for automatic DI registration
+     *
+     * Uses environment-aware configuration (development or production)
+     * based on APP_ENV from Environment service.
+     */
     #[Initializer]
-    public function initialize(Container $container): void
+    public static function initialize(Container $container): void
+    {
+        // Get Environment from container (proper framework pattern)
+        $env = $container->get(Environment::class);
+        $appEnv = $env->getString(EnvKey::APP_ENV, 'production');
+
+        // Determine configuration based on environment
+        $configuration = match ($appEnv) {
+            'development', 'local', 'dev' => MiddlewareConfiguration::development(),
+            'staging' => MiddlewareConfiguration::production(), // Staging uses production config
+            default => MiddlewareConfiguration::production(),
+        };
+
+        $provider = new self($configuration);
+        $provider->registerServices($container);
+    }
+
+    /**
+     * Register all middleware services in the container
+     */
+    private function registerServices(Container $container): void
     {
         $this->registerMiddlewareConfiguration($container);
         $this->registerMiddlewareComponents($container);