- Implement AcceptInvitationUseCase with validation
- Check invitation status, expiration, and email match
- Auto-create WorkspaceMember on accept
- Handle case when user is already a member
- Implement DeclineInvitationUseCase to reject invitations
- Update invitation status (accepted/declined/expired)
- Add 9 comprehensive unit tests (all passed)
Phase 4 Task 14/68 completed
- 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
- Implement CreateWorkspaceUseCase with subscription plan support
- Auto-configure quotas based on plan (free/pro/enterprise)
- Auto-create owner membership record on workspace creation
- Validate workspace name (required, max 100 chars)
- Validate owner user exists before creation
- Add 7 comprehensive unit tests (all passed)
Phase 4 Task 12/68 completed