Enhance WordChat Pro functionality with WooCommerce product support, conversation history handling, and new admin features

- Added support for syncing WooCommerce products, including price, SKU, stock status, and short description.
- Implemented conversation history handling in chat queries, limiting to the last 6 messages.
- Introduced AJAX handlers for custom Q&A management (list, add, update, delete).
- Updated admin settings to allow exclusion of specific pages from displaying the chat widget.
- Enhanced chat widget with a preview feature and improved error handling for user experience.
- Updated readme to reflect compatibility with WordPress 6.7.
