refactor: separate standalone and managed room configs

- veins → shunts rename
- add cfg/standalone/ and cfg/<room>/ structure
- remove old data/*.json (moved to cfg/<room>/data/)
- update build.py and ctrl scripts

ctrl/stop.sh

@@ -1,7 +1,20 @@
 #!/bin/bash
 # Stop soleprint Docker container
+#
+# Usage:
+#   ./stop.sh              # Stop standalone
+#   ./stop.sh amar         # Stop amar
 
 set -e
-cd "$(dirname "$0")/../gen"
+cd "$(dirname "$0")/.."
 
+TARGET="${1:-standalone}"
+GEN_DIR="gen/$TARGET"
+
+if [ ! -d "$GEN_DIR" ]; then
+    echo "$GEN_DIR not found"
+    exit 1
+fi
+
+cd "$GEN_DIR"
 docker compose down