Tweak mob roaming logic and a few other values

This fixes the crash with mobs with a very small m_iIdleRange and avoids
unnecessary looping.

Co-authored-by: JadeShrineMaiden <69916714+JadeShrineMaiden@users.noreply.github.com>

src/MobManager.hpp

@@ -70,7 +70,7 @@ struct Mob : public BaseNPC {
         data = d;
 
         regenTime = data["m_iRegenTime"];
-        idleRange = (int)data["m_iIdleRange"] * 2; // TODO: tuning?
+        idleRange = (int)data["m_iIdleRange"];
         dropType = data["m_iDropType"];
         level = data["m_iNpcLevel"];