Stand-alone test under src/tests/strToNum exercising every PStringUtils
method (Split / IsInt / IsFloat / ToInt / ToDouble / IsEqualNoCase /
ContainsNoCase / BeginsWithNoCase). Three modes: built-in pass/fail
suite, ad-hoc inspection of command-line strings, and an interactive
prompt. Adds -h/--help and -i/--interactive options. Pure C++17, no
ROOT dependency.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>