feat : init Central project — Symfony 8 + Nuxt 4 + Docker starter

Same architecture as Lesstime: API Platform 4, JWT auth, @malio/layer-ui,
PostgreSQL 16, Docker Compose (ports 8083/3003/5436), dark mode theme.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

public/index.php

@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Kernel;
+
+require_once dirname(__DIR__).'/vendor/autoload_runtime.php';
+
+return function (array $context) {
+    return new Kernel($context['APP_ENV'], (bool) $context['APP_DEBUG']);
+};