Feature Request: Add `lat update` command to update lat.md to the latest version

Feature Description

Add a convenience command/alias lat update that updates lat.md to its latest version globally by executing npm i -g lat.md.

Use Case / Rationale

Users frequently want a quick, built-in way to update lat.md directly from the CLI without needing to remember or manually type out the full global npm install command (npm i -g lat.md). Adding lat update improves developer ergonomics and provides a seamless way to keep lat.md up to date.

Proposed Behavior

Running lat update in the terminal would:

1. Run npm i -g lat.md (or equivalent global npm update command).
2. Display progress and confirm successful update to the latest version.