Add Sloppybee MCP Server

[walter7007]

Name: Sloppybee
Description: Create shareable task lists with AI-powered generation
npm: @sloppybee/mcp-server
GitHub: https://github.com/walter7007/mcp-server
Category: Productivity

[koic]

Since #3046, new entries are no longer added to the README's third-party server list. Going forward, please consider registering it in the MCP Registry. Thank you.