fix: fix this mess

I am stupid
I am stupid
I am stupid
I can't believe how f- ricking stupid I am

furvm/include/furvm/fwd.hpp

@@ -111,7 +111,7 @@ using function_id = std::uint16_t;
 /**
  * @brief A handle to a furvm function.
  */
-using function_h = handle<function, generic_header<function_id>>;
+using function_h = handle<function, refcount_header<function_id>>;
 
 // module.hpp
 

furvm/include/furvm/thing_allocator.hpp

@@ -69,8 +69,9 @@ public:
     [[nodiscard]] T* allocate(std::size_t count = 1) {
         for (auto it = m_deadThings->begin(); it != m_deadThings->end(); ++it) {
             if (it->second != count) continue;
+            T* data = it->first;
             m_deadThings->erase(it);
-            return it->first;
+            return data;
         }
         return m_arena->allocate<T>(count);
     }

furvm/src/executor.cpp

@@ -101,7 +101,7 @@ thing_h executor::pop_thing() {
     if (m_frames.top().stackBase >= m_stack.size()) throw stack_underflow();
     thing_h top = std::move(m_stack.top());
     m_stack.pop();
-    return top;
+    return std::move(top);
 }
 
 thing_h executor::thing() const {