feat: English wiki pages — full bilingual wiki (DE + EN)
New pages (12 English module pages):
GrumpyWelcome-EN, GrumpyMod-EN, GrumpyTickets-EN,
GrumpyVoice-EN, GrumpyMusic-EN, GrumpyHelp-EN, GrumpyCommands-EN,
GrumpyReactionRoles-EN, GrumpyLeveling-EN, GrumpySuggestions-EN,
GrumpyPolls-EN, GrumpyStarboard-EN
Updated pages:
Home.md — English section added after German content
_Sidebar.md — English navigation section added (GrumpyCore Wiki English)
Wiki is now fully bilingual: German pages unchanged, English equivalents
accessible via -EN suffix links in sidebar and Home.md
