I am sorry.
This is my take. He cannot set the rules in your house. That is bad for him and worse for you.
If he has pot, I would call the police every time. Likewise, for stealing. First off I would lock up everything so that he cannot get access. Second, I would consider taking the door off his room, and blocking access to the basement or any other area that he can hide (making sure all emergency exits are clear.) Calling the police about illegal behavior is best for him and for you. If you do not there could be legal consequences for you.
If he has stated flat out he will not accept your authority, what about emancipated minor status? What about a foster placement? (Thinking about it this might be child abandonment, so, forget it.)
I just googled foster placement as an option for parents, and a list of websites came up on handling defiant children. Lots of other parents must be in the same position. I googled emancipation of a minor and read the summary on Nolo Press. For this status your son would need to request it and also have a means of support.
The more I think about it, this could be an idea. You know what your son's stated priority is: to go out of state where Pot is legal and he can grow it. Fine. If your son knew you would agree with his petition to emancipate, it might motivate him to get a job, with the idea of emancipating at 16 and moving out of state away from your authority. Why not help him out? Working with what he does want, what does motivate him, and trying to remove the barriers to his attaining it.
The NOLO website did suggest the use of a mediator to settle parent child disputes. I do not see how effective this would be, because what would be the consequence of his non-compliance with agreements?
He is basically saying to you F/U. Why not call it what it is: He is rejecting completely your role as his parent. Turn it around, and let him have what he wants, if there is a way to legally do so. Just not in your home. You could tell him you would support his emancipation.
I know this may sound radical. After all parents are supposed to rear their children, not cut them lose. The thing is this: he is removing that as an alternative. To fight him on it, in my experience makes it worse. There is war in your house, and you are the casualty.
If you are old enough, think about young Muhammad Ali in the ring. Dance Like a Butterfly, Sting like a bee. That would be your son.
I wish I could think of more appealing alternatives, but I think it would not be a good idea to accept his terms.
In the meantime are there before school and after school programs he can enroll him in, so that time at home is less? Weekend activities, likewise.
He asked for this, not you. I would not feel one bit of guilt. You are not obligated to give him frills, just necessities. (I remember when my son was doing something similar to me. I was still buying him Wild Caught Salmon at Costco. He is a health nut. This was not the best course to take.)
I might speak with a professional to make a plan. I would be firm in my own mind about the plan before I uttered one word to your son. I might communicate your terms in a neutral environment, not your own home.
I did not do as I am telling you. It was a mistake.
Keep posting. If you can find the time, the more you can post the easier this is to bear. I am sorry this is happening to you.