Data retention message needs better visual integration in chat history

Steps to reproduce

1. Click on the History icon in the AI Side Panel
2. Observe the "Inactive chats are deleted after 30 days" message placement and styling

Current behavior

• The data retention message appears as a prominent gray box that breaks the visual flow of the chat history In Chat History, it sits awkwardly between the header and the first chat entries

Expected behavior

• The retention message should be styled more subtly (smaller text, less prominent background, or no background)
• The message should feel integrated into the interface rather than interrupting the content flow