Ghost roles create new minds, better tracking of roles at round end screen (#5175)

* Ghost roles now get new Minds

* Some round start/end button stuff

* Mind tracking for better round end reports

* Make traitor kill objectives use mind CharacterName rather than actual occupied entity ("kill brain" prevention)

* Transition over to EntityUid for mind stuff because that's the only way to do it

* BrainSystem fix for PR rebase

Content.Server/Mind/MindTrackerSystem.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Collections.Generic;
+using Content.Server.GameTicking;
+using Content.Server.Mind.Components;
+using Content.Shared.GameTicking;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.ViewVariables;
+using Robust.Shared.Player;
+
+namespace Content.Server.Mind
+{
+    /// <summary>
+    /// This is absolutely evil.
+    /// It tracks all mind changes and logs all the Mind objects.
+    /// This is so that when round end comes around, there's a coherent list of all Minds that were in play during the round.
+    /// The Minds themselves contain metadata about their owners.
+    /// Anyway, this is because disconnected people and ghost roles have been breaking round end statistics for way too long.
+    /// </summary>
+    public class MindTrackerSystem : EntitySystem
+    {
+        [ViewVariables]
+        public readonly HashSet<Mind> AllMinds = new();
+
+        public override void Initialize()
+        {
+            base.Initialize();
+
+            SubscribeLocalEvent<RoundRestartCleanupEvent>(Reset);
+            SubscribeLocalEvent<MindComponent, MindAddedMessage>(OnMindAdded);
+        }
+
+        void Reset(RoundRestartCleanupEvent ev)
+        {
+            AllMinds.Clear();
+        }
+
+        void OnMindAdded(EntityUid uid, MindComponent mc, MindAddedMessage args)
+        {
+            var mind = mc.Mind;
+            if (mind != null)
+                AllMinds.Add(mind);
+        }
+    }
+}
+