… variables are accessible

This PR updates the `bootstrap` file to use `getenv()` instead of `$_ENV` when retrieving environment variables.

In some PHP configurations, `$_ENV` returns `null` unless the `variables_order` setting in `php.ini` includes the `E` flag. This can cause Octane to fail when resolving the application base path or vendor directory.

By switching to `getenv()`, Octane can reliably fetch environment variables without requiring users to modify their PHP configuration.

### Changes
- Replaced `$_ENV['APP_RUNNING_IN_CONSOLE']` with `getenv('APP_RUNNING_IN_CONSOLE')`.
- Ensured `COMPOSER_VENDOR_DIR` and other variables are resolved consistently.

### Why
When extending the Swoole server start process and attempting to change the vendor file path, `$_ENV` returned `null` unless `variables_order` was explicitly configured. This fix ensures smoother setup for developers across different environments.

### Impact
- No breaking changes.
- Improves reliability of environment variable handling in Swoole/Octane bootstrap.