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>

.claude/launch.json

@@ -0,0 +1,11 @@
+{
+    "version": "0.0.1",
+    "configurations": [
+        {
+            "name": "dmtools",
+            "runtimeExecutable": "symfony",
+            "runtimeArgs": ["serve", "--no-tls"],
+            "port": 8000
+        }
+    ]
+}