Accept post creation time in message contract

packages/api-contracts/src/messages.ts

@@ -23,6 +23,7 @@ export const SentMessageSchema = z.strictObject({
   postUrl: z.string().optional(),
   postImageUrl: z.string().optional(),
   postImageAnalysis: z.string().optional(),
+  postCreatedAt: z.number().optional(),
   owner: RedditAccountOwnerSchema.optional(),
 });
 export const MessagesResponseSchema = z.array(SentMessageSchema);