Migrate to type-safe model ID structs

PluralKit.Core/Database/Functions/MessageContext.cs

@@ -10,18 +10,18 @@ namespace PluralKit.Core
     /// </summary>
     public class MessageContext
     {
-        public int? SystemId { get; }
+        public SystemId? SystemId { get; }
         public ulong? LogChannel { get; }
         public bool InBlacklist { get; }
         public bool InLogBlacklist { get; }
         public bool LogCleanupEnabled { get; }
         public bool ProxyEnabled { get; }
         public AutoproxyMode AutoproxyMode { get; }
-        public int? AutoproxyMember { get; }
+        public MemberId? AutoproxyMember { get; }
         public ulong? LastMessage { get; }
-        public int? LastMessageMember { get; }
-        public int LastSwitch { get; }
-        public IReadOnlyList<int> LastSwitchMembers { get; } = new int[0];
+        public MemberId? LastMessageMember { get; }
+        public SwitchId LastSwitch { get; }
+        public MemberId[] LastSwitchMembers { get; } = new MemberId[0];
         public Instant LastSwitchTimestamp { get; }
         public string? SystemTag { get; }
         public string? SystemAvatar { get; }

PluralKit.Core/Database/Functions/ProxyMember.cs

@@ -8,7 +8,7 @@ namespace PluralKit.Core
     /// </summary>
     public class ProxyMember
     {
-        public int Id { get; }
+        public MemberId Id { get; }
         public IReadOnlyCollection<ProxyTag> ProxyTags { get; } = new ProxyTag[0];
         public bool KeepProxy { get; }