Simplify: fix fallback bug, reduce redundancy, restore step PHPDocs

- FailureShowListener: fix show_tmp_dir fallback '' -> sys_get_temp_dir()
  (bug introduced by duplication with MinkContext::showLastResponse)
- SauceLabsFactory: simplify `is_bool($x) ? $x : (bool) $x` -> `(bool) $x`
- MinkExtension::load: extract $baseUrl/$browserName locals to avoid
  evaluating the same `?? ''` expression twice per line
- EnvironmentCapabilities: store TRAVIS_JOB_NUMBER and JENKINS_HOME
  getenv() results before the switch to avoid double calls per match
- MinkContext: restore PHPDoc comments on all step methods (Example lines
  for discoverability); keep PHP attributes, no @Given/@When/@Then tags

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

src/Behat/MinkExtension/ServiceContainer/Driver/SauceLabsFactory.php

@@ -39,7 +39,7 @@ class SauceLabsFactory extends Selenium2Factory
     public function buildDriver(array $config): Definition
     {
         $host = 'ondemand.saucelabs.com';
-        if (is_bool($config['connect']) ? $config['connect'] : (bool) $config['connect']) {
+        if ((bool) $config['connect']) {
             $host = 'localhost:4445';
         }