If somebody locked me in a room all day I'd scream my head off too. I don't think getting this dog to stop barking should be your main issue here.
First and foremost, I would talk to my roomie. Maybe if she knows the distress her dog is in she will change her behaviour.
You didn't take this animal in, it isn't your responsibility and I realize asking you to take it out of the crate and give it the attention and stimulation it needs is an unfair request, but try to sympathize with this poor dog. Can you make time for it at all?
If you can't make any time for this dog, then yes, I'd look into animal cruelty laws. I don't know if this counts of cruelty or not (I know nothing about the laws) but it sure sounds horrible and cruel and if the situation can't be changed this dog needs a better home.
This might be able to be handled as a room mate courtesy request instead of calling out your roomie as an "animal abuser". I would certainly try that route first. If you have equal stake in the living arrangements then your room mate definately overstepped her boundries getting a dog without your agreement. Make is CLEAR that you are unhappy with the curent situation and ask her to consider appropriate changes.
Now for the dog's welfare, a proper crate training protocol is important for new puppies. If you have no choice but to be a part of this puppy's daily life then it would benefit you and your room mate to do a bit of research on the subject. Working together with your room mate to train the puppy properly will make for a wonderful addition to your life.
It sounds like this situation has been forced upon you and that really sucks. I see you as having a few options. Become a proactive part of this puppy's life, shut yourself off from the situation or find another living arangement. Either way you need to confront your room mate.
That is WAY too much time in a cage. Poor puppy. Your roommate needs to be educated quickly about canines & their needs. It seems to me like the roommate got this dog on a whim and is not really prepared to give what the dog needs. If you have the time/inclination, taking that poor dog out of its confinement to play with it would be a very kind thing to do.
And yes, if the dog has no access to water, that IS cruelty.
First, young puppies like this can become dehydrated very, very quickly. This is a real concern. The puppy should always have access to water (with the exception of limiting water a bit before bedtime), especially at this age. Definitely a concern, and very scary.
Second, yes, it's a huge amount of time for a puppy to be in a crate. The thing is, lots of people use a crate as a tool in potty training. So, they basically keep the puppy in the crate unless they are feeding, playing with it, taking it out to potty, or walking/exercising it. The reason is, to limit access to the house in case of accidents, and, also, because dogs usually don't pee/poop where they sleep, so it is supposed to encourage them to learn to hold it.
I personally have never liked using crates for this reason, I prefer to have the puppy out with the family, and just watch super close to deal with potty training issues. But, using the crate can work, and if it's done right, it's not cruel.
The thing is, it seems like your roommate isn't doing it right. Yes, it's kind of normal to keep the puppy crated when the owner is at work. It's for potty training, and to keep the puppy safe from getting into things in the house that can hurt it, or to keep the puppy from destroying things in the house. But, if you keep the puppy crated all day, it's a good idea to hire a dog walker to let the puppy out halfway through the day, to pee/poop, and get a bit of exercise.
And, if you keep the puppy crated during the work day, you'd want to make up for it by spending lots and lots of time with him after work and on weekends.
Puppies need so much at this age, to help them become happy, healthy, well adjusted dogs. I could go on and on....
You're in a tough situation. It isn't your dog, and as concerned as you are, there really isn't anything you can do about your roomie's treatment of the dog in the end. You can offer advice, or provide her with some tips, but, the problem is, how do you do that without implying she's not doing a good job and offending her.
Another poster mentioned that you could go at it from the angle of a somewhat disgruntled roommate. The noise, and getting a dog without your agreement, that sort of thing. That's an idea, too.
As for cruelty, the lack of water is super close if not already an issue that could be pursued. Check into animal laws in your area.
What if you got her a puppy raising book for an early Christmas present, seeing that she's suddenly become "interested" in puppies? Anything from Ian Dunbar is great!