feat(assessment): implement Question Bank and Exam Generator backend

feat: implement question bank and exam modules with associated services, controllers, and entities

feat: implement question bank and exam modules with associated services, controllers, and entities

feat(backend): add student payment APIs and stabilize transcript/assignment responses.

fix(database): normalize FK column types for refactored schema sync

refactor: resolve circular dependencies and optimize entities for SWC builder

feat(attendance): face references, AI section flow, and nullable photo file

Scheduling templates done

before testing

all sprint 4 dev b endpoints works fine

before testing endpoints

Clean initial commit without secrets