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>

config/packages/security.yaml

@@ -29,6 +29,7 @@ security:
     # Note: Only the *first* matching rule is applied
     access_control:
         - { path: ^/login$, roles: PUBLIC_ACCESS }
+        - { path: ^/puzzle/, roles: PUBLIC_ACCESS }
         - { path: ^/, roles: IS_AUTHENTICATED_FULLY }
 
     role_hierarchy: