bcc3089f53
- Implement InviteMemberUseCase with role-based permission check - Only owner/admin can invite members (not regular members) - Cannot invite as owner (owner is unique per workspace) - Check for duplicate invitations and existing members - Generate invitation token with 7-day expiration - Send invitation email with accept link - Add 7 comprehensive unit tests (all passed) Phase 4 Task 13/68 completed