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>

config/packages/framework.yaml

@@ -0,0 +1,12 @@
+# see https://symfony.com/doc/current/reference/configuration/framework.html
+framework:
+    secret: '%env(APP_SECRET)%'
+
+    # Note that the session will be started ONLY if you read or write from it.
+    session: true
+
+when@test:
+    framework:
+        test: true
+        session:
+            storage_factory_id: session.storage.factory.mock_file