Improve attribute parser

[ganyicz]

The scenario

These syntaxes were broken:

{{-- JavaScript inside attribute values produced ghost attributes --}}
<flux:menu.item x-data="{
    init() {
        this.document.title = '{{ $title }}';
    }
}">

{{-- @ attributes silently dropped --}}
<x-button @click="handle" />

The problem

The old AttributeParser used hand-rolled regexes that were buggy and inconsistent with Laravel.

• We would match this.document.title = '{{ ... }}' inside the x-data JavaScript as a separate attribute.
• Attributes with @ symbols were silently dropped because the old regex didn't include @.

The solution

Replace the old attribute parsing with Laravel's own approach from ComponentTagCompiler::getAttributesFromAttributeString():

1. Run Laravel's full preprocessing pipeline on attribute strings before parsing, to avoid further drift.
2. Use Laravel's attribute regex, added as LaravelRegex::ATTRIBUTE_PATTERN:

const ATTRIBUTE_PATTERN = '/
    (?<attribute>[\w\-:.@%]+)
    (=(?<value>("[^"]+"|\'[^\']+\'|[^\s>]+)))?
/x';