iEduPortal Stage 120 — Super Administrator Management Centre

This release adds a protected administration workspace for:
- School sessions: create/edit
- School terms: create/edit
- Classrooms: create/edit
- Staff: create/edit; supported roles include Class Teacher, Subject Teacher, Front Desk, Head Teacher, Principal, School Nurse, Accountant, Driver, Nanny and Other
- Classroom assignment to class/subject teachers
- Subject teaching assignments through a dedicated relation table created automatically if absent
- Pupils: create/edit and link to a parent/guardian and classroom
- Parent quick-create from pupil management
- Fees: create/edit by session, term and classroom
- Automatic fee obligation creation for every active pupil in the selected classroom; existing obligations are never deleted during fee edits

Security:
- Super-administrator API accepts only authenticated admin bearer tokens with admin/super_admin role.
- New account passwords are stored using password_hash().
- API input is validated and database writes use prepared statements.
- No browser token persistence is introduced.

Compatibility:
- Existing legacy application and Stage 119 functionality are preserved.
- No SQL import is required. The staff_subject_assignment table is created automatically by the protected administration API when needed.

Verification:
- stage120.php: ALL CHECKS PASSED
- PHP syntax: PASS
- JavaScript syntax: PASS
- PWA cache: v76
