Add MedMind recovery and Steam authentication

Models/PasswordResetChallenge.cs

@@ -0,0 +1,18 @@
+using MongoDB.Bson;
+using MongoDB.Bson.Serialization.Attributes;
+using System;
+
+namespace GameAuthApi.Models;
+
+public class PasswordResetChallenge
+{
+    [BsonId]
+    [BsonRepresentation(BsonType.ObjectId)]
+    public string Id { get; set; }
+    public string UserId { get; set; }
+    public string CodeHash { get; set; }
+    public int FailedAttempts { get; set; }
+    public DateTime ExpiresUtc { get; set; }
+    public DateTime CreatedUtc { get; set; }
+    public bool Used { get; set; }
+}