Replace ServerStartCommand with WorkerRunner

FrankenPHP workers are PHP files started by the frankenphp binary, not console commands.
Extract the frankenphp_handle_request() loop into Http\WorkerRunner so apps can use it
directly from worker.php. Remove src/Command/ as it's no longer needed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Http/WorkerRunner.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace Pronchev\Pinecore\Http;
+
+use Pronchev\Pinecore\ExceptionHandler;
+
+final class WorkerRunner
+{
+    public function __construct(
+        private readonly HttpApplication  $app,
+        private readonly ExceptionHandler $exceptionHandler,
+    ) {}
+
+    public function run(): void
+    {
+        $maxRequests = (int) ($_SERVER['MAX_REQUESTS'] ?? 0);
+
+        for ($n = 0; !$maxRequests || $n < $maxRequests; ++$n) {
+            $keepRunning = frankenphp_handle_request(function (): void {
+                try {
+                    $this->app->handleRequest($_GET, $_POST, $_COOKIE, $_FILES, $_SERVER);
+                } catch (\Throwable $e) {
+                    $this->exceptionHandler->handleException($e);
+                }
+            });
+
+            $this->app->terminate();
+            gc_collect_cycles();
+
+            if (!$keepRunning) {
+                break;
+            }
+        }
+    }
+}