feat: what is new since my last visit, and turning a comment into a ticket

Opening a ticket notes the visit and answers the one before (issue_visits),
so the page marks others' comments and changes since. A comment can become
a ticket of its own, as a subtask or linked; it remembers where it went.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/api/tracker/domain/src/lib/events/index.ts

@@ -17,6 +17,7 @@ export * from './comment-edited.event';
 export * from './comment-reacted.event';
 export * from './comment-decision-marked.event';
 export * from './comment-thread-resolved.event';
+export * from './comment-turned-into-issue.event';
 export * from './issue-review.events';
 export * from './comment-poll.events';
 export * from './comment-deleted.event';