fix: remove incorrect npm --jobs flag and override zmq dependency

- Removed '--jobs 1' from npm install (was causing npm to try and install a package named '1').
- Added 'zmq' to overrides in package.json to prevent ancient native build failures.

backend/package.json

@@ -16,6 +16,7 @@
   },
   "overrides": {
     "mdns2": "$mdns2",
-    "node-uuid": "^1.4.8"
+    "node-uuid": "^1.4.8",
+    "zmq": "$zmq"
   }
 }

scripts/setup.sh

@@ -186,13 +186,13 @@ cd "$REAL_HOME/mpvj/backend"
 echo "Installing backend dependencies..."
 # Use --package-lock=false to ignore any committed lockfiles that might be polluted
 rm -rf node_modules package-lock.json
-sudo -u "$REAL_USER" npm install --jobs 1 --omit=optional --package-lock=false
+sudo -u "$REAL_USER" npm install --omit=optional --package-lock=false
 
 cd "$REAL_HOME/mpvj/frontend"
 if [ ! -d "dist" ]; then
   echo "Installing frontend dependencies and building..."
   rm -rf node_modules package-lock.json
-  sudo -u "$REAL_USER" npm install --jobs 1 --omit=optional --package-lock=false
+  sudo -u "$REAL_USER" npm install --omit=optional --package-lock=false
   sudo -u "$REAL_USER" npm run build
 else
   echo "Pre-built frontend detected. Skipping frontend build."