Objectives all use a consistent definition of "dead" defined in Mind now. DieCondition is no longer inverted. (#4006)

More brain fixes, mainly

Content.Server/Mobs/Mind.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
+using Content.Shared.GameObjects.Components.Mobs.State;
 using Content.Server.GameObjects.Components.Mobs;
 using Content.Server.GameObjects.Components.Observer;
 using Content.Server.Mobs.Roles;
@@ -106,6 +107,41 @@ namespace Content.Server.Mobs
             }
         }
 
+        /// <summary>
+        ///     True if this Mind is 'sufficiently dead' IC (objectives, endtext).
+        ///     Note that this is *IC logic*, it's not necessarily tied to any specific truth.
+        ///     "If administrators decide that zombies are dead, this returns true for zombies."
+        ///     (Maybe you were looking for the action blocker system?)
+        /// </summary>
+        [ViewVariables]
+        public bool CharacterDeadIC
+        {
+            get
+            {
+                // This is written explicitly so that the logic can be understood.
+                // But it's also weird and potentially situational.
+                // Specific considerations when updating this:
+                //  + Does being turned into a borg (if/when implemented) count as dead?
+                //    *If not, add specific conditions to users of this property where applicable.*
+                //  + Is being transformed into a donut 'dead'?
+                //    TODO: Consider changing the way ghost roles work.
+                //    Mind is an *IC* mind, therefore ghost takeover is IC revival right now.
+                //  + Is it necessary to have a reference to a specific 'mind iteration' to cycle when certain events happen?
+                //    (If being a borg or AI counts as dead, then this is highly likely, as it's still the same Mind for practical purposes.)
+
+                // This can be null if they're deleted (spike / brain nom)
+                if (OwnedEntity == null)
+                    return true;
+                var targetMobState = OwnedEntity.GetComponentOrNull<IMobStateComponent>();
+                // This can be null if it's a brain (this happens very often)
+                // Brains are the result of gibbing so should definitely count as dead
+                if (targetMobState == null)
+                    return true;
+                // They might actually be alive.
+                return targetMobState.IsDead();
+            }
+        }
+
         /// <summary>
         ///     Gives this mind a new role.
         /// </summary>