refactor(actions): centralize core page request/csrf guards

pages/flash/dismiss($id).php

@@ -2,17 +2,17 @@
 
 use MintyPHP\Http\Request;
 use MintyPHP\Router;
-use MintyPHP\Session;
 use MintyPHP\Support\Flash;
 
-$target = Request::safeReturnTarget(requestInput()->bodyAll()['return'] ?? '');
+$request = requestInput();
+$target = Request::safeReturnTarget($request->bodyAll()['return'] ?? '');
 
-if (requestInput()->method() !== 'POST') {
-    Router::redirect($target);
+if (!actionRequirePost($target)) {
+    return;
 }
 
-if (!Session::checkCsrfToken()) {
-    Router::redirect($target);
+if (!actionRequireCsrf($target, flashOnFailure: false)) {
+    return;
 }
 
 $flashId = isset($id) ? trim((string) $id) : '';