Replace '== null' with 'is null' and '!= null' with 'is not null'
across 19 core files following modern C# pattern matching conventions.
Only literal null comparisons are changed. Assignments, value
comparisons, and LINQ expressions are left untouched.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
* Create item moving helper class
* Change the method calling order for joined game
Dispatch bot after things are initialized such as inventories
* Add GetItemMovingHelper ChatBot method