Support experimental HTTP middleware in HttpServerRunner constructor

[clue]

This changeset adds experimental support for passing HTTP middleware to the HttpServerRunner constructor. The goal is to raise the built-in web server's 64 KiB request body limit, but this can also be used to preprocess or filter requests before they reach X:

$container = new FrameworkX\Container([
    FrameworkX\Runner\HttpServerRunner::class => function (?string $X_LISTEN = null) {
        return new FrameworkX\Runner\HttpServerRunner(
            new FrameworkX\Io\LogStreamHandler('php://output'),
            $X_LISTEN,
            [
                new React\Http\Middleware\StreamingRequestMiddleware(),
                new React\Http\Middleware\LimitConcurrentRequestsMiddleware(10),
                new React\Http\Middleware\RequestBodyBufferMiddleware('8M'),
                new React\Http\Middleware\RequestBodyParserMiddleware('2M')
            ]
        );
    }
]);

$app = new FrameworkX\App($container);

Note that this is an experimental feature and the API may be subject to change in future releases. Once X handles larger request bodies on its own, this may no longer be needed, but for now this avoids having to patch X. The first commit also makes sure a failure to create the HTTP server no longer leaves the listen address bound.

Without any middleware given, the HTTP server behaves exactly as before, so this should be safe to apply.

Builds on top of #294, #295, #292, #224, #237, #117, #156, #13 and others
Refs #234, #293, #196, #193 and #190

[Copilot]

Copilot review overview

🟢 Approval recommended

No blocking issues were identified; one minor documentation clarification remains.

Review effort: Lite
Findings: None

What changed in this PR

Adds experimental HTTP middleware support to HttpServerRunner, with safer server initialization and configurable request-body handling.

Changes:

• Adds middleware validation and execution.
• Prevents binding when server creation fails.
• Adds tests and documentation for request-body limits.

File	Summary
tests/​Runner/​HttpServerRunnerTest.php	Tests middleware, validation, buffering, and cleanup.
src/​Runner/​HttpServerRunner.php	Adds middleware support and safer initialization.
docs/​best-practices/​deployment.md	Documents middleware configuration and request limits; clarify the stated 100 MiB memory bound.
docs/​api/​request.md	Documents default request-body limits.

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