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>

frontend/i18n/i18n.config.ts

@@ -0,0 +1,4 @@
+export default defineI18nConfig(() => ({
+    legacy: false,
+    locale: 'fr',
+}))