iEduPortal Stage 6 — Secure Authentication Migration

UPLOAD:
Extract this package into the existing school-management-system/public/ directory.
This package intentionally replaces only the four existing login pages plus
the new upgrade/core and upgrade/stage6 files.

IMPORTANT:
- Do not edit connection.php.
- Do not import SQL.
- Back up the working site/database before upload.
- The current login form remains visually the same.

SECURITY CHANGE:
The old password-in-SQL authentication is replaced with prepared statements.
GET-based username/password login paths are removed so passwords are not sent
in URLs. On a successful normal login, an existing legacy plaintext password
is immediately upgraded to password_hash(). Existing hashed passwords are
verified with password_verify().

TEST:
1. Open:
https://YOUR-DOMAIN/school-management-system/public/upgrade/stage6/
2. It should report PASS.
3. Then test the normal login page for at least one account you can safely
   access (Admin, Staff, Parent, or Pupil).
4. Confirm that the login still reaches its normal dashboard.

If a login fails, stop and report the screenshot/error before testing another
account. Do not proceed to Stage 7 until Stage 6 is confirmed.
