- Add internal/scripts/UIConfig.ps1: module-scoped $script:UIConfig hashtable
  centralizing all colors, layout constants, display strings, HelpOptions list,
  and CommonParameters list that were previously hardcoded across both public
  functions.

- Add internal/functions/Get-ScrollableListView.ps1: single reusable function
  replacing three near-identical slice+indicator rendering blocks (command list,
  parameter list, help content) in Show-ModuleCommandViewer.

- Add internal/functions/Get-CommandHelpContent.ps1: extracts the help-fetching
  logic (Examples/Detailed/Full/Online) that was copy-pasted into both the
  RightArrow and Enter handlers of the HelpOptions view (~50 lines x2).

- Add internal/functions/Get-SortedParameterList.ps1: extracts the
  non-common-first parameter sort that was duplicated 3 times in the handler
  blocks and dead scriptblocks.

- Add internal/functions/Get-ParameterHelpContent.ps1: extracts the
  Get-Help -Parameter fetch+escape block duplicated in both RightArrow and
  Enter handlers of the ParameterList view.

No public function behavior is changed in this phase. The public functions
continue to work identically; the helpers are wired in during Phase 2.