Release v0.2.4

- max_request=100000 default — bounded worker recycling for long-running
  PHP, with ZEALPHP_MAX_REQUEST env var override.
- Scaffold defaults to coroutine mode (App::superglobals(false)) — aligns
  with the documented "recommended for new projects" stance and sidesteps
  the worker-state-leak class of issues for greenfield apps.
- Framework default (App::$superglobals = true) is unchanged for backward
  compatibility with existing installs upgrading via composer update.