Scaffold Symfony 8 app with Bootstrap/DataTables and Docker stack

- Symfony 8.1 webapp skeleton on PHP 8.5 (AssetMapper/importmap, no Node)
- Form-login gate: User entity, security.yaml, SecurityController,
  app:user:create command, initial migration (user + messenger_messages)
- Bootstrap 5 + DataTables layout (base/login/home templates); any
  table.datatable is auto-initialised
- trusted_proxies/headers wired for the shared Nginx Proxy Manager
- Docker (servers only): docker-compose.yml (php:8.5-fpm-alpine,
  nginx:1.30-alpine, mariadb:12.3; host ports 8085/3310; external
  docker_default network) + docker/{Dockerfile,php.ini,nginx,setup.sh,restart.sh}
- .env with CHANGEME placeholders (no secrets), .gitattributes enforces
  LF so the deploy scripts stay runnable on Linux

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

config/packages/routing.yaml

@@ -0,0 +1,10 @@
+framework:
+    router:
+        # Configure how to generate URLs in non-HTTP contexts, such as CLI commands.
+        # See https://symfony.com/doc/current/routing.html#generating-urls-in-commands
+        default_uri: '%env(DEFAULT_URI)%'
+
+when@prod:
+    framework:
+        router:
+            strict_requirements: null