BizCore v4.0.2 HOTFIX

Fixes:
- MariaDB error in update-4.0.1.php caused by prepared SHOW TABLES LIKE ?
- Uses information_schema.tables for safe table verification.
- Keeps v4.0 production connected to BizCore's actual `items` table.
- Initializes banking, cheque, cash-flow and production navigation variables before rendering.

INSTALL:
1. Upload ZIP to existing BizCore root and Extract > Overwrite.
2. Open: https://ceylongemx.online/update-4.0.2.php
3. Confirm all table checks show OK.
4. Click Apply / Verify v4.0.2.
5. Ctrl + F5.
6. Open Production > Production Dashboard.

Do not rerun update-4.0.php if its production tables already exist.
