fix(tests): use $commandParameterNames in the param-help assertion

This repo's older scaffolding had drifted: the param-help Context asserted against
$parameterNames, which is never defined (only $commandParameterNames exists). The
discovery-phase fix activates that Context, so correct the variable. Surfaced by
Copilot on ReScenePS #21.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: tablackburn

tests/Help.tests.ps1

@@ -238,7 +238,7 @@ Describe "Test help for <_.Name>" -ForEach $commands {
 
         # Shouldn't find extra parameters in help
         It 'finds help parameter in code: <_>' {
-            $_ -in $parameterNames | Should -Be $true
+            $_ -in $commandParameterNames | Should -Be $true
         }
     }
 }