Mind tweaks & fixes (#21203)

Content.Client/Mind/MindSystem.cs

@@ -4,4 +4,24 @@ namespace Content.Client.Mind;
 
 public sealed class MindSystem : SharedMindSystem
 {
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<MindComponent, AfterAutoHandleStateEvent>(OnHandleState);
+    }
+
+    private void OnHandleState(EntityUid uid, MindComponent component, ref AfterAutoHandleStateEvent args)
+    {
+        // Because minds are generally not networked, there might be weird situations were a client thinks multiple
+        // users share a mind? E.g., if an admin periodical gets sent all minds via some PVS override, but doesn't get
+        // sent intermediate states? Not sure if this is actually possible, but better to be safe.
+        foreach (var (user, mind) in UserMinds)
+        {
+            if (mind == uid)
+                UserMinds.Remove(user);
+        }
+
+        if (component.UserId != null)
+            UserMinds[component.UserId.Value] = uid;
+    }
 }