BizCore v6.1.2 - Mundo Images & UI

1. Extract this ZIP into the BizCore root (ceylongemx.online) and overwrite files.
2. Open /update-6.1.2.php as Super Admin.
3. Open Mundo Online Products and upload a JPG/PNG/WEBP image (max 5 MB).
4. Save with the current logged-in user's password.
5. Open /mundo/?refresh=1 to force an immediate fresh catalog.

Changes:
- Adds ecommerce_products.online_image_path safely.
- Adds Mundo-specific image upload, preview and remove fallback.
- Catalog API now sends full image URL + category + brand.
- Storefront CSS cache-busting fixes stale/basic-looking UI.
- Empty cached catalog automatically refreshes once.
- Existing business/Mundo data are preserved.
