feat(admin): wire dashboard modules and implement calendar persistence

Issue #15 #17 #24 #26 Fixed

feat(enrollments): add endpoint for live student enrollment count

feat: add database test script for office hour slots retrieval

feat(ta-dashboard): unlock live TA APIs on existing routes

Merge branch '004-frontend-backend-contracts'

Courses MANAGEMENT AND ASSIGNING DONE

feat(courses): allow administrative course deletion and refine entities

feat: admin API to assign/remove Instructor and TA for course sections

fix(enrollments): refactor period retrieval and service integration

added swagger feature and fixed some errors in the "files" feature

Enrollment Feature DONE AND TESTED SUCCESFULLY