[BUG] Scheduled tasks sidebar not updated after removal via chat

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When scheduled tasks are completed (one-time tasks that have fired) or removed/disabled via a chat interaction, they remain visible in the Claude Desktop sidebar. They only disappear after restarting the app.

The underlying state is correct — the tasks are properly marked as disabled/completed on disk — but the sidebar UI does not reflect the change until a full app restart.

What Should Happen?

The sidebar should reactively update when scheduled tasks are removed, disabled, or completed via chat interaction, without requiring an app restart.

Steps to Reproduce

1. Have one or more scheduled tasks visible in the Claude Desktop sidebar
2. In a chat session, remove or disable a scheduled task (e.g., via the update_scheduled_task MCP tool with enabled: false, or after a one-time fireAt task completes)
3. Observe: the task remains in the sidebar
4. Restart the app
5. Observe: the task is now gone from the sidebar

Claude Model

Claude Opus 4.6

Is this a regression?

Not sure / not applicable

Claude Code Version

Claude 1.1.6041 (62e193) 2026-03-10T20:11:22.000Z

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

N/A (Claude Desktop)

Additional Information

This is distinct from #35131 (tasks disappearing after upgrade/migration). This bug is about live UI reactivity — the sidebar not subscribing to or polling for changes to the scheduled tasks state when modifications happen through chat interactions.