fix: Prevent resolveCastSource from being instantiated with void type

Add `requires(!std::is_void_v<T>)` constraint to resolveCastSource to
reject void type at compile time.

Author: engsr6982

src/jspp/binding/traits/Polymorphic.h

@@ -51,6 +51,7 @@ struct ResolvedCastSource {
 };
 
 template <typename T>
+    requires(!std::is_void_v<T>)
 ResolvedCastSource resolveCastSource(T* value) {
     auto& engine = EngineScope::currentEngineChecked();