fix: require Docker Compose v2 in scripts and docs

compose 1.29.2 aborts with KeyError: 'ContainerConfig' against Docker 28,
which broke the deploy on the prod VM.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

scripts/deploy.sh

@@ -6,8 +6,9 @@ set -euo pipefail
 PROXY_DIR="${PROXY_DIR:-/srv/elevenlabs}"
 cd "${PROXY_DIR}"
 
-COMPOSE="docker-compose"
-command -v docker-compose >/dev/null 2>&1 || COMPOSE="docker compose"
+# compose v1 (1.29.x) breaks against Docker 28 with KeyError: 'ContainerConfig' — prefer v2
+COMPOSE="docker compose"
+docker compose version >/dev/null 2>&1 || COMPOSE="docker-compose"
 
 echo "=== [1/4] Pulling latest image ==="
 ${COMPOSE} pull