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>

postcss.config.cjs

@@ -0,0 +1,7 @@
+module.exports = {
+    parser: 'postcss-scss',
+    plugins: {
+        '@tailwindcss/postcss': {},
+        'autoprefixer': {},
+    },
+}