### Summary
- Adds some more checks in case a corpse's owner is somehow null. Would like to eventually allow null owner corpses, but more work is needed.
- Cleans up variable unboxing and reassignment in quests. Also flattens quest logic. Still more work needs to be done.
- Codegens more quest items/mobiles.
### Summary
Modifying a ValueLinkList using one of the methods will bump the "version". This field is used by iterators (foreach loops) to determine if the link list was modified while iterating. The sector.Items (and in the future other lists), will no longer be safe to modify while iterating. The server will _CRASH_ if the ValueLinkList is modified.
Thanks to @stefanomerotta for help!
### Screenshots
<img width="588" alt="image" src="https://github.com/modernuo/ModernUO/assets/3953314/83ee0b6e-ff4f-4768-9e29-84456e04b1ec">
