refactor(forum): migrate topic page to canonical path URLs
- move topic rendering from legacy include to controller/use case flow
- add ForumTopicPathService routing for /forum/{sectionPath}/{topicSlug}-{topicId}/ and legacy redirects
- persist unique topic slug in DB with installer/update script (update_980_990)
- replace legacy topic links (?type=topic&id=) across forum, admin forum pages, and profile activity