Custom Portals Foxified

feat(config): integrate KwahsCore with config screen, SafeConfig, and sound muting

• Split CPConfig into CLIENT (mute sounds) and COMMON (gameplay rules) specs
• Add config screen via KwahsConfigScreen with dual-spec auto-greying
• Replace all raw .get() calls with SafeConfig wrappers
• Add validateOrReset for both specs on startup
• Mute custom portal trigger/travel sounds via PlaySoundEvent (client-only)
• Guard IConfigScreenFactory behind dist check for dedicated server safety
• Use intField for unbounded range values, slider for bounded portal size
• Add KwahsCore srcDir + JarJar build integration