- New statuses: under_review
- New DB fields: assigned_to, assigned_by, assigned_at, due_date (migration 012)
- HandoverNotificationService: emails on assign and review-request
- HandoverService: assign(), submitForReview(), resendNotification()
- Assign page: manager selects employee + due date, resend notification
- Create wizard: manager can assign during creation (step 1)
- Edit page: "Submit for review" button for assignee, assign link for manager
- List page: open/closed tabs, non-managers see only their assigned handovers
- Email templates: handover_assigned + handover_review_requested (de/en)
- i18n keys added for de and en
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
