[FEATURE] /clear command support in agent sdk v2 for context clean up

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

We are trying to implement session hot reuse for all users with their message history without close and recreate a session, a fully disentanglement between user messages and sessions would be very benificial to the performance of our agent sdk server, thx

Proposed Solution

Send /clear command like prompt:"/clear" in agent sdk v1

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_