Threads: add Slack/Discord thread sessions

src/auto-reply/templating.ts

@@ -15,10 +15,13 @@ export type MsgContext = {
   SessionKey?: string;
   /** Provider account id (multi-account). */
   AccountId?: string;
+  ParentSessionKey?: string;
   MessageSid?: string;
   ReplyToId?: string;
   ReplyToBody?: string;
   ReplyToSender?: string;
+  ThreadStarterBody?: string;
+  ThreadLabel?: string;
   MediaPath?: string;
   MediaUrl?: string;
   MediaType?: string;