Multi-Chat Support and Connectivity Checks

Features

• Added support for multi-session chat tabs, so you can keep multiple conversations open at the same time. Create a new tab with Alt+T / Option+T, rename tabs, and close other tabs or tabs to the right from the tab context menu.
• Added a Network Diagnostics panel in Settings to help check Qoder service connectivity and troubleshoot network-related issues.

Improvement

• Improved chat session reliability by syncing tab loading states and preventing duplicate tabs when opening conversation history.
• Improved the stability of commit message generation and Mermaid rendering.