Feature Request: Allow users to customize the ChatGPT new-chat greeting

It would be great if ChatGPT allowed users to set a personalized greeting for new chats, similar to how ChatGPT already provides a personalized experience through memory, personality, and custom instructions.

Instead of always showing the standard greeting, users could choose or write their own greeting that appears when they open a new chat.

For example:

Welcome back. What are we pretending to be productive about today?