refactor: improve Object property management with duplicate prevention, memory cleanup, and updated VTK interface tests

src/Core/Property.h

@@ -103,6 +103,7 @@ public:
   // Accessors
   const T& Get() const { return *m_value; }
   void Set(const T& value) {
+    if (!m_value) return;
     T val = value;
     if constexpr (std::is_arithmetic<T>::value) {
       if (m_HasRange) { if (val < m_Min) val = m_Min; if (val > m_Max) val = m_Max; }