Dispatch renders raw <system-reminder> tags in user message bubbles

Description

When Claude desktop injects a <system-reminder> timestamp tag into user messages (via the desktop app's built-in session hook), the Dispatch view renders the raw XML tag visibly in the message bubble instead of stripping it.

Claude Code (terminal/Code tab) correctly ignores the tag. Dispatch does not.

Steps to Reproduce

1. Open Claude desktop → Cowork → Dispatch
2. Send any message from the Dispatch input
3. The sent message bubble shows the raw tag prepended above the actual message text:

<system-reminder>Message sent at Sun 2026-06-14 18:10:01 UTC.</system-reminder>
your actual message here

Expected Behavior

The <system-reminder> tag should be stripped from the visible message bubble, matching the behavior of the Code tab and terminal interface.

Environment

• Claude desktop v1.12603.1.0 (Windows 11 Pro)
• Observed in the Dispatch (Beta) view under Cowork