Add application source code, configs and assets

- Controllers, Entity, Repository, Services, Twig extensions
- Templates (account, emails, home, legal, security, unsubscribe)
- Symfony config updates (bundles, security, framework, services)
- Vite + Bun setup with PostCSS
- Caddy config, CLAUDE.md, README
- Update .gitignore (node_modules, .idea, cert)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker/caddy/Caddyfile

@@ -0,0 +1,13 @@
+:80 {
+    root * /app/public
+
+    php_fastcgi php:9000 {
+        trusted_proxies private_ranges
+    }
+
+    file_server
+
+    encode gzip
+
+    try_files {path} /index.php?{query}
+}