ByteCode currently has viewFromStack(N) which returns TagValueView, but moveFromStack(N) still returns a raw FastTuple<bool, TypeTags, Value>. This forces call sites to wrap the result manually:

auto x = TagValueMaybeOwned::fromRaw(moveFromStack(0));

Add a moveOwnedFromStack(N) method that returns TagValueMaybeOwned directly, completing the RAII accessor trio:

• viewFromStack(N) → TagValueView (non-owning peek)
• moveOwnedFromStack(N) → TagValueMaybeOwned (ownership transfer)

Then sweep all call sites in vm_builtin*.cpp and vm_block.cpp that use the fromRaw(moveFromStack(...)) pattern and replace with moveOwnedFromStack(...).