Squashes upstream 13.x changes from v13.6.0 to v13.7.0 into a single commit. 13,623 tests pass (was 13,535). Fledge PHP 8.5 optimizations preserved in Arr, FormRequest (array_any), Application (typed VERSION const), Worker (Revolt fiber signals), and PrefersJsonResponses (array_all). Adds symfony/polyfill-php86 for the new SortDirection enum (PHP 8.6 feature backported for Fledge's 8.5 baseline).