Add delete_scheduled_task tool to scheduled-tasks MCP

Summary

The scheduled-tasks MCP currently exposes three tools: create_scheduled_task, list_scheduled_tasks, and update_scheduled_task. There is no way to delete a scheduled task.

Problem

When a scheduled task becomes orphaned (e.g. its SKILL.md file is deleted or its directory no longer exists), there is no way to remove it. Disabling via update_scheduled_task stops execution but the task definition persists, and Claude Desktop logs ENOENT errors on every startup:

[error] [ScheduledTasks] Failed to read task file for tool-health-check: ENOENT: no such file or directory, open '...\Scheduled\tool-health-check\SKILL.md'

This repeats for every orphaned task, every time Claude Desktop initializes a session.

Request

Add a delete_scheduled_task tool that accepts a taskId and fully removes the task definition so it no longer appears in list_scheduled_tasks and no longer triggers errors.

Workaround

Currently the only option is update_scheduled_task with enabled: false, which stops execution but does not stop the error spam.