BizCore v4.2 - Production Costing & Profitability

INSTALL
1. Take full file and database backups.
2. Upload this ZIP to the existing BizCore project root.
3. Extract > Overwrite.
4. Open https://ceylongemx.online/update-4.2.php
5. Click Install v4.2 Update.
6. Ctrl + F5.

WHAT CHANGES
- Estimated material cost uses current warehouse average cost and planned quantities.
- Actual material cost uses actual material + wastage at weighted-average cost.
- Labour, overhead and other production costs can be entered per batch.
- Finished goods stock IN is valued at FULL production cost, not material-only cost.
- Selling price is snapshotted when the batch is completed.
- Profit/unit and gross margin are locked with the completed batch.
- New Production Cost Report supports date and product filters.

IMPORTANT
For a clean test, create a NEW production batch after installing v4.2.
Historical v4.1 completed batches are not silently revalued.
