UNIPOS Super Admin navigation patch

1. Back up public_html/pos_reports/admin.php
2. Upload admin.php from this ZIP to public_html/pos_reports/ and overwrite only admin.php.
3. Keep the previously installed shop-name login.php and .htaccess from UNIPOS_SHOP_NAME_URL_FIX.zip.
4. Open https://unicomlb.com/pos_reports/admin.php

Changes:
- Remove Shop Admin/User Login link from Super Admin sign-in.
- Remove generic Shop Login link from logged-in Super Admin header.
- Add Shop Login link inside each shop heading, pointing to /pos_reports/{shop-name-slug}/shop_login.php.

Notes:
- Existing accounts, POS worker, and data are unchanged.
- URL is based on the shop name. Renaming a shop changes its URL.
- Ensure shop names produce unique URL slugs; duplicate slugs cannot be used for login.
