There is nothing on the market.
If you make one yourself, some reinforcing may be in order since the receiver is aluminum.
Here is something to consider: Drill a hole in the stock (and receiver?) behind the ejection port and around 1/2" below... You need to drill through the receiver, trigger group and the right side of the stock. You will need a rod that is say 1/4" dia. and long enough to be able to touch the left (in)side of the stock when inserted in the hole, plus enough to be bent at a 90° angle and touch the bolt handle.... Eh, I'll just do a quick MSpaint mock for you:
This isn't something I've made (no interest for me), so I can't say if it will get in the way of any parts... but the BHO comes to mind.
It's simple, and will work. It's made up of only one part (if you want it to be immediately removable) and you can make a plug for the hole while the rod is removed. If you want it to stay in the receiver for a extended time, you can (think of other ways) drill a hole in the rod near the wall of the inside of the receiver, then slip a washer or two over the rod and stick a pin in the hole... Yes, there are other ways of keeping it in there and also other methods of holding the bolt closed, but I'll leave that up to you to think of them.
Here's a bit of a tip, buy a can of liquid rubber and dip the forward end of the rod in it so that it won't mar the bolt handle.
ETA: Imade a typo in the pic, it shouls say "rod" instead of "pin".