One that might work is to keep your bike in your room but always keep it upside down, on its saddle / handlebars, and leave a spanner on the floor next to it. That way you can claim that it's inside because you're working on it. It also means it won't be leaning up against the wall leaving tell-tale marks. Invest in a cheapo rug or table runner to put it on to protect the floor.
One that might work is to keep your bike in your room but always keep it upside down, on its saddle / handlebars, and leave a spanner on the floor next to it. That way you can claim that it's inside because you're working on it. It also means it won't be leaning up against the wall leaving tell-tale marks. Invest in a cheapo rug or table runner to put it on to protect the floor.