fix(core-typings): make author_link optional in MessageQuoteAttachment and prevent null md

createQuoteAttachment was propagating null/undefined md from messages.
Now only spreads md when truthy. Also author_link was never set in
createQuoteAttachment so it must be optional in the type.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ggazzo

apps/meteor/lib/createQuoteAttachment.ts

@@ -9,7 +9,7 @@ export function createQuoteAttachment(
 ) {
 	return {
 		text: message.msg,
-		md: message.md,
+		...(message.md && { md: message.md }),
 		...(isTranslatedMessage(message) && { translations: message?.translations }),
 		message_link: messageLink,
 		author_name: message.alias || getUserDisplayName(message.u.name, message.u.username, useRealName),

packages/core-typings/src/IMessage/MessageAttachment/MessageQuoteAttachment.ts

@@ -5,7 +5,7 @@ import type { MessageAttachmentBase } from './MessageAttachmentBase';
 
 export type MessageQuoteAttachment = {
 	author_name: string;
-	author_link: string;
+	author_link?: string;
 	author_icon: string;
 	message_link?: string;
 	text: string;