This pull request introduces a WebSocket-based live reload feature to the Marmite development server, allowing browsers to automatically refresh when site files change during development. It adds a new live reload script endpoint, injects the script into served HTML files, and manages live reload connections and notifications. The documentation is updated to explain how to use the new feature.

Live reload feature:

• Added a WebSocket-based live reload system, including a new LiveReload struct for managing client connections and sending reload notifications when site files change. [1] [2] [3]
• Injected a live reload script snippet into served HTML files when live reload is enabled, and exposed the script at /__marmite__/livereload.js. [1] [2]
• Updated the server to handle WebSocket upgrade requests at /__marmite__/livereload and broadcast reload events to connected clients. [1] [2]

Configuration and dependency updates:

• Added the tungstenite crate for WebSocket support and updated server code to accept an optional LiveReload argument. [1] [2] [3]

Documentation:

• Updated the README.md with instructions for enabling live reload in development, including how to add the script snippet to templates.