iEduPortal Stage 4 — Authentication Foundation

UPLOAD:
Extract this package into the existing school-management-system/public/ directory.
Do not delete or replace unrelated application files.

TEST:
Open:
https://YOUR-DOMAIN/school-management-system/public/upgrade/stage4/

This stage is additive. It introduces a reusable authentication layer that:
- uses prepared statements for authentication lookups
- supports password_hash/password_verify
- can recognize the current legacy plaintext passwords
- can upgrade a verified legacy password to a secure hash later

The Stage 4 test performs read-only/probe operations only. It does not change
database records or replace the current login pages.

After PASS, confirm Stage 4 before proceeding.
