BizCore v2.1 User Account & Employee Login Linking

INSTALL
1. Take a full BizCore files backup.
2. Export the BizCore database.
3. Upload this ZIP to:
   /public_html/ceylongemx.online/
4. Extract and overwrite.
5. Login as Super Admin.
6. Open:
   https://ceylongemx.online/update-2.1.php
7. Click Install v2.1 Update.

WHAT TO TEST
1. Open Users.
2. Confirm Add User is visible.
3. Create a normal user with a temporary password.
4. Assign GMS Infinite Holdings.
5. Keep Require password change enabled.
6. Login using the new account and confirm Change Password opens.
7. Open an employee without a linked login.
8. Click Create Login.
9. Confirm the employee is linked and workspace assignments synchronize.

SECURITY
- Passwords are stored using PHP password_hash().
- Duplicate email accounts are blocked.
- Temporary passwords can require a change at first login.
- A Super Admin cannot deactivate or remove their own current Super Admin access.
- Employee login creation is restricted to Super Admin.
