Robot vacuums have come a long way, and Costco’s current lineup features self-cleaning docks, mopping capabilities, and smart mapping — all at members-only prices. The Roborock QX Revo Robot Vacuum and Mop ($399.99 after $100 off, 2,504 reviews) is the best value pick. With a multifunctional dock that washes and dries the mop pads automatically, it’s the set-it-and-forget-it dream. Over…