Feature: Update installed Skills using `boost:update` or similar

I have been using Skills in Laravel Boost since it was introduced and it has been working great so far, until I wanted to update the Skills I installed using `boost:add-skill`.

# Context

Using [Vercel's Skills CLI](url) I noticed with every installed Skill it introduces a file to keep track of Skills installed version and also it provides a `npx skills update` command.

Example of a `skills-lock.json` file:
```json
{
"version": 1,
"skills": {
"frontend-design": {
"source": "anthropics/skills",
"sourceType": "github",
"computedHash": "063a0e6448123cd359ad0044cc46b0e490cc7964d45ef4bb9fd842bd2ffbca67"
}
}
}

```

Introducing a similar system to Laravel Boost will be very good addition since Boost already has the `boost:add-skill` command.

Boost could introduce a similar system but using the already existent `boost.json` file, and/or also create a `skills-lock.json` file for interoperability with the Vercel's Skills CLI.

And after introducing a system to keep track of installed Skills, with a source and installed version/hash/tag then introducing a Skills update step in `boost:update` and/or introduce a new `boost:update-skills` command that performs this action.

Start by tracing the existing boost:add-skill and boost:update commands, then inspect how boost.json is currently used. Compare the proposed tracking approaches with Vercel's skills-lock.json and npx skills update behavior. Done means the project has a defined installation-tracking format and a clear command or update step for updating installed Skills.

Written by the indexing model from the issue text.