Introduce a Batch Add Teachers feature that allows authorized users (e.g., School Admin, Head Teacher) to quickly assign multiple teachers to a selected class by selecting from an existing list of teachers in the school.

Key Functional Requirements:

• Display the full teacher list of the school when user selects "Batch Add"

• Support multi-select (checkbox) to assign multiple teachers at once

• Show confirmation before finalizing the assignment

• Display success/failure status after adding

• Role-based permission: only authorized users can access this feature