Fix npm run start to run everything.

We can run the project locally with a single command now.

scripts/start-all-dev.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cleanup() {
+  echo
+  echo "Stopping frontend and backend..."
+  local pids
+  pids="$(jobs -p || true)"
+  if [ -n "$pids" ]; then
+    kill $pids 2>/dev/null || true
+    wait $pids 2>/dev/null || true
+  fi
+}
+trap cleanup INT TERM EXIT
+
+echo "Starting backend..."
+npm run backend:start &
+
+echo "Starting frontend..."
+npm run frontend:dev &
+
+wait