Add shared multiplayer gear puzzle (Chamber of Motion)

Players open a no-login link and see live cursors and dragged gear
pieces synced in real time, backed by a small Workerman WebSocket
relay (src/Command/PuzzleRelayCommand.php) run alongside symfony
serve - no Docker/Mercure hub needed. The board renders the wall
artwork with a spare-gears tray, and a "Reset puzzle" button (visible
only to logged-in users, verified server-side via a signed token) lets
the DM wipe the shared state for everyone.

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

composer.json

@@ -44,7 +44,8 @@
         "symfony/web-link": "8.1.*",
         "symfony/yaml": "8.1.*",
         "twig/extra-bundle": "^2.12|^3.0",
-        "twig/twig": "^2.12|^3.0"
+        "twig/twig": "^2.12|^3.0",
+        "workerman/workerman": "^5.2"
     },
     "config": {
         "allow-plugins": {