1## MODIFIED Requirements23### Requirement: Task assignment4A task SHALL have at most one assignee, and the assignee MUST be a member of the task's project. Changing the assignee SHALL emit an assignment event consumed by the notifications capability.56#### Scenario: Assign to project member7- **WHEN** a member assigns a task to another member of the same project8- **THEN** the task's assignee is updated9- **AND** an assignment event is recorded for the new assignee1011#### Scenario: Assign to non-member12- **WHEN** a member assigns a task to a user who is not in the project13- **THEN** the system rejects the request with a 403 error14- **AND** the existing assignee is unchanged1516#### Scenario: Unassign a task17- **WHEN** a member clears the assignee of a task18- **THEN** the task has no assignee19- **AND** no assignment event is recorded