feat(sprint7): Phase 3 — Forum MVP

- Flyway V15: forum_topics, forum_replies, forum_reactions, forum_reports tables
- Enums: ForumTargetType, ReactionType, ReportStatus
- Extended AuditEventType with FORUM_REPLY_CREATED, FORUM_REPORT_REVIEWED
- Entities: ForumTopic, ForumReply, ForumReaction, ForumReport
- Repositories: ForumTopicRepository, ForumReplyRepository, ForumReactionRepository, ForumReportRepository
- ForumService: full CRUD, moderation (lock/pin/delete), 60-min edit window,
  toggle reactions, content reporting, notifications on new topics/replies
- ForumController: admin + portal endpoints (topics, replies, reactions, reports, moderation)
- Frontend: forum.ts service with React Query hooks (admin + portal)
- Frontend: Admin forum page with topic list, moderation actions (lock/pin/delete)
- Frontend: Portal forum page with topic list, reply thread, reactions, report
- Navigation: added Forum with MessageSquare icon
- i18n: forum.* keys in de.json and en.json

cannamanage-frontend/src/data/navigations.ts

@@ -44,6 +44,11 @@ export const navigationsData: NavigationType[] = [
         href: "/calendar",
         iconName: "Calendar",
       },
+      {
+        title: "Forum",
+        href: "/forum",
+        iconName: "MessageSquare",
+      },
       {
         title: "Personal",
         href: "/settings/staff",