BizCore v2.7 Purchasing, GRN & Opening Stock Hotfix

INSTALL
1. Take full files and database backups.
2. Upload this ZIP to /public_html/ceylongemx.online/
3. Extract and overwrite.
4. Open https://ceylongemx.online/update-2.7.php
5. Click Install v2.7 Update.
6. Press Ctrl + F5.

CRITICAL HOTFIX
stock-opening.php, stock-transfer.php and stock-adjustment.php no longer call
the missing require_business_unit() function. They now validate the selected
workspace using current_business_unit_id().

PURCHASING
- Purchase order list/create/view
- Supplier selection from CRM Supplier contacts
- GRN list/create/view
- Receive against a PO or create a direct GRN
- Automatic purchase stock movements
- Automatic warehouse stock balance recalculation
- PO partial/full receiving status
- Batch, serial and expiry receiving fields

TEST
1. Select Infinite Cashew.
2. Ensure a supplier contact is assigned to Infinite Cashew.
3. Ensure a stock-tracked item and CASH-MAIN warehouse exist.
4. Test Opening Stock first.
5. Create a Purchase Order.
6. Click Receive Goods.
7. Post the GRN to CASH-MAIN.
8. Check Stock Summary and Stock Ledger.
