[FEATURE]:cancel prompt

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Feature Request

When the agent is currently processing a prompt, newly submitted prompts are queued and will be processed afterward.

It would be useful to have a way to cancel/remove a prompt that is currently queued before the agent starts processing it.

Example

1. The agent is processing Prompt A.
2. The user sends Prompt B, which gets queued.
3. The user realizes Prompt B was incorrect or no longer needed.
4. The user should be able to cancel Prompt B while it is still queued.
5. Prompt A should continue running normally.

Expected behavior

Prompt A → RUNNING
Prompt B → QUEUED → CANCEL ❌
Prompt C → QUEUED

After cancelling:
Prompt A → RUNNING
Prompt C → QUEUED

Cancelling a queued prompt should not interrupt the currently running task.

Motivation

This would be useful when a user accidentally sends a prompt, changes their mind, or realizes that a queued instruction is no longer relevant before the agent starts processing.