feat(validator): add file upload validation rules

src/Libs/Request.php

@@ -76,10 +76,17 @@ class Request extends Neuron
             default => $this->get
         };
 
+        // Merge uploaded files ($_FILES) into the body data set so the file rules
+        // (file/image/mimes and the routed min/max/required...) can validate
+        // uploads through a Request. $this->post is left untouched.
+        $body = empty($_FILES)
+            ? $actual
+            : new Neuron(array_merge(get_object_vars($actual), $_FILES));
+
         if (
             Validator::validateList(static::paramRules(), $this->params) &&
             Validator::validateList(static::getRules(), $this->get) &&
-            Validator::validateList(static::rules(), $actual)
+            Validator::validateList(static::rules(), $body)
         ) {
             return true;
         }