iEduPortal Stage 3 — Database Foundation (Diagnostic Fix 2)

UPLOAD:
Copy/overwrite the contents of this package into the existing school-management-system/public/ directory.
Only the upgrade/stage3 and upgrade/core files are part of this package.

TEST:
Open:
https://ieduportal.com/school-management-system/public/upgrade/stage3/

This version searches upward for the existing legacy connection.php and shows the actual safe diagnostic if the database test fails. It performs SELECT-only checks and does not modify application tables or records.
