[13.x] Add HTTP idempotency middleware

[WendellAdriel]

Overview

This PR adds first-class idempotency handling for write requests so applications can safely retry POST, PUT, and PATCH operations without duplicating work.

Approach

• add a configurable middleware that scopes and stores request fingerprints and responses
• replay matching responses, reject conflicting reuse, and guard concurrent in-flight duplicates
• expose the middleware through the default alias map and controller attributes, with integration coverage for the main request flows

Examples

Route::post('/orders', OrderController::class)
    ->middleware(Idempotent::using(ttl: 600));

#[Idempotent]
class OrderController
{
    public function __invoke(): Response
    {
        // ...
    }
}

class OrderController
{
    #[Idempotent(scope: 'user')]
    public function store(): Response
    {
        // ...
    }
}

[shaedrich]

You can add types here:

Suggested change

	* @param \Closure $next
	* @param \Closure(\Illuminate\Http\Request): \Symfony\Component\HttpFoundation\Response $next

[shaedrich]

You could work with the constants here:

Suggested change

	throw new HttpException(400, "Missing required header: {$header}");
	throw new HttpException(Response::HTTP_BAD_REQUEST, "Missing required header: {$header}");