Add new piper/stiff plot options to Shiny App

Piper plots and stiff plots now have the options to omit outliers and use Alkalinity if HCO3 is missing, add these arguments to the Shiny App

Start by locating the Shiny App entry point and the existing Piper and stiff plot argument handling. Trace how plot options are passed into the app, then add controls for omitting outliers and using Alkalinity when HCO3 is missing. Done means both plots expose and honor these options.

Written by the indexing model from the issue text.