feat(story-1.1): scaffold Symfony 7.4 LTS app with DDEV, Messenger, Scheduler

- DDEV config: PHP 8.4, PostgreSQL 16, nginx-fpm, Imagick via webimage_extra_packages
- Symfony 7.4 LTS skeleton + webapp pack scaffolded via Composer
- Removed AssetMapper, Stimulus, UX-Turbo (replaced by Vue 3 SPA per architecture)
- Added symfony/messenger + symfony/scheduler (Doctrine transport)
- Gitea CI workflow: PHP 8.4 container + PostgreSQL 16 service, runs phpunit

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

config/packages/framework.yaml

@@ -0,0 +1,15 @@
+# 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
+
+    #esi: true
+    #fragments: true
+
+when@test:
+    framework:
+        test: true
+        session:
+            storage_factory_id: session.storage.factory.mock_file