Fix Load File crash: VALUEPARM for literal field arg in CTCL_GetAutoSlotInt

Script calls callback(CTCL_GetAutoSlotInt, k, 0/1/2/3) where 0-3 are
integer literals. The script engine passes literals as (void*)N directly
(not as pointers), so INTPARM(1) = *((int*)data[1]) dereferences NULL
when field=0, producing the 'Attempt to read from NULL' STOP.

Fix: VALUEPARM(1) = (int)data[1] reads the value without dereferencing.
k (data[0]) remains INTPARM because it is a script variable (passed as
a pointer to the variable's storage, not a literal).

Also add exists(@ConLobbyMission@) guard before MAIL_SET_ROOKIE_MISSION
for defensive safety if the sub-script is not running.

Rebuild required: MW4.exe (Release + Profile).

Gameleap/mw4/Content/ShellScripts/ConLobby.script

@@ -1681,7 +1681,8 @@ main
         if callback($$CTCL_LoadAutoFile$$)
         {
             // Apply mission + game options via existing Rookie Mission flow
-            mail(MAIL_SET_ROOKIE_MISSION, @ConLobbyMission@)
+            if exists(@ConLobbyMission@)
+                mail(MAIL_SET_ROOKIE_MISSION, @ConLobbyMission@)
             // Clear all slots
             o_cam_list.nselected = 0
             for (k = 0; k < nRosterCount; k++)