fix: make sure platform binary exists (#7676)

ui/desktop/scripts/check-lockfile-platforms.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+# Verify package-lock.json has cross-platform optional dependency entries.
+#
+# npm has a bug where running `npm install` with an existing node_modules/
+# prunes platform-specific entries from the lockfile, breaking CI on other platforms.
+# See: https://github.com/npm/cli/issues/4828
+#
+
+set -euo pipefail
+
+LOCKFILE="${1:-package-lock.json}"
+
+fail=0
+grep -q '"node_modules/@esbuild/win32-x64"' "$LOCKFILE" || { echo "MISSING: @esbuild/win32-x64"; fail=1; }
+grep -q '"node_modules/@esbuild/linux-x64"' "$LOCKFILE" || { echo "MISSING: @esbuild/linux-x64"; fail=1; }
+
+if [ "$fail" -eq 1 ]; then
+  echo ""
+  echo "ERROR: package-lock.json is missing cross-platform optional dependencies."
+  echo "This happens when 'npm install' is run with an existing node_modules/ directory."
+  echo ""
+  echo "To fix, run from ui/desktop/:"
+  echo "  rm -rf node_modules package-lock.json"
+  echo "  npm install"
+  echo ""
+  echo "Then commit the regenerated package-lock.json."
+  exit 1
+fi
+
+echo "OK: package-lock.json has cross-platform entries"