[Demo] Remove runtime/frankenphp-symfony dependency

No longer needed with Symfony 8.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Author: OskarStark

demo/composer.json

@@ -12,7 +12,6 @@
         "mrmysql/youtube-transcript": "^0.0.5",
         "nyholm/psr7": "^1.8",
         "php-http/discovery": "^1.20",
-        "runtime/frankenphp-symfony": "^0.2.0",
         "symfony/ai-bundle": "@dev",
         "symfony/ai-chroma-db-store": "@dev",
         "symfony/ai-clock-tool": "@dev",