[Feature Request] Share conversation among users

**Describe the solution you'd like**
Like customized-bot sharing, conversation sharing is also preferable.

**Why the solution needed**
Sharing examples with other users can trigger the expansion of LLM usage to improve teams' productivity.

**Additional context**
Add any other context or screenshots about the feature request here.

No files, tests, or entry points are identified in the issue, so begin by locating the conversation and customized-bot sharing flows. Define the sharing scope, permissions, and expected user experience before implementation; done should include an agreed design and tests for sharing conversations among users.

Written by the indexing model from the issue text.