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/services/dto/user-data.ts

@@ -0,0 +1,12 @@
+export type UserData = {
+    id: number
+    '@id'?: string
+    username: string
+    roles: string[]
+}
+
+export type UserWrite = {
+    username: string
+    plainPassword?: string
+    roles: string[]
+}