[BUG] Slash commands should not be queued or sent to Claude

Environment

• Claude CLI version: 0.2.108

Bug Description

Queued slash commands are sent to Claude instead of processed locally immediately.

Steps to Reproduce

1. Ask Claude to do something.
2. Whilst it thinks, run /cost

Expected Behavior

Cost of current session should be shown immediately.

Actual Behavior

It gets sent to Claude who then speculates about the true nature of its existence (just kidding, it tells me to RTFM).

Additional Context

<img width="1211" alt="Image" src="https://github.com/user-attachments/assets/32ea3e05-29b9-45e7-9148-2e8224396046" />