Feature: Change exit code to RESTART_EXIT_CODE

### Describe your feature request or suggestion in detail

Change exit code to RESTART_EXIT_CODE to distinguish from a manual shutdown so that a script can do maintenance and restart the server or allow for a manual exit

### Describe a possible solution to your feature or suggestion in detail

current: sWorld->ShutdownServ(preAnnounceSeconds, SHUTDOWN_MASK_RESTART, SHUTDOWN_EXIT_CODE);
proposed: sWorld->ShutdownServ(preAnnounceSeconds, SHUTDOWN_MASK_RESTART, RESTART_EXIT_CODE);

### Additional context

_No response_

Search the module for the shown sWorld->ShutdownServ call and for the definitions or usages of RESTART_EXIT_CODE and SHUTDOWN_EXIT_CODE. Confirm that the restart path returns a distinct exit code while manual shutdown behavior remains unchanged, then build the module and run any available checks.

Written by the indexing model from the issue text.