Fix the JavaScript hook example in the Livewire 3 skill

[sulimanbenhalim]

The JS hooks example in the Livewire 3 skill has two hooks in it, and neither one fires on v3.

message.failed is a Livewire 2 hook. The v3 upgrade guide lists it under "New lifecycle hooks" as one of the four message.* hooks folded into commit, with the old body moving into the fail() callback. Nothing dispatches message.failed in v3, so that handler is dead.

The 419 check has the wrong shape. It reads fail.status, but fail is the callback registrar, not the failure object. status shows up on the callback's argument, so fail is truthy, fail.status is undefined, and the branch never runs. The guide covers this exact case under "Page expired hook", since it's the documented replacement for v2's Livewire.onPageExpired():

Livewire.hook('request', ({ fail }) => {
    fail(({ status, preventDefault }) => {
        if (status === 419) {
            preventDefault()
            confirm('Your custom page expiration behavior...')
        }
    })
})

I followed that, kept the skill's original alert() text, and included preventDefault() like the guide does, otherwise Livewire's own page-expired dialog fires on top of the alert.

Looks like the example started as a port of the Livewire 2 skill's onPageExpired() / onError() pair and the shape got lost on the way over. It's the only JS example in the skill, so right now an agent following it writes session-expiry and failure handling that silently does nothing.

Covers item 4 of #895, the rest of that issue is untouched. One .ai file, no test, same as #918 and #913.