I have only read the first page and then just your comments OP.
I have a thirteen year old boy and am a lone parent and appreciate how intense the relationship can be. I've always said to my ds that him laying a hand on me will never be acceptable and that one day he would be taller than me and stronger so even as a little kid it was a really firm boundary that he knew would mean serious serious stuff if it was crossed.
I would like you to think of yourself too. When ds has had periods of being badly behaved or foul tempered at home I've sat him down and said I cannot live like this, I will not put up with this atmosphere in my own home and I deserve peace and niceness in my own home.
I've made it really clear that his behaviour effects me and that that is not ok. He's a teenager and struggles with his temper sometimes and identifies that he just wants to hit things when he's angry and talk about it later when he's calmed down. He has a decent free-standing boxing bag in his room that he asked for from me last Christmas and he does know to go and channel it into that.
I think he knows that if he ever crossed the line and was physical with me I would take extreme action. I've made clear I would not be willing to live with anyone ever who was violent towards me no matter who they were.
I think you have to hammer home your side of things as a start and ask him what would you do/how would you feel if you saw somebody else hitting me? I would presume he is protective and would respond with something like I'd batter/kill/whatever them. You then need to ask how it is different for him to treat you like this.
I would be spelling out that you were on a road that was unsustainable and would likely lead to him having to live elsewhere if you continue on down that road. That yes you love him but no you won't be anyone's punch bag and if he forces you to you will have to have him moved out of your home.
I hope to god I never find myself in that situation and ds's temper is directed at objects not me and he is well aware of my boundaries and how I absolutely hold my boundaries because he has known me for the last 13 years and knows I don't allow people to mistreat him for long and there are limited chances I give even to people I love.
You so have my sympathy because I can imagine how awful the situation must be. Ds is frequently damned hard work to get up and to school on time and I hate how it has to be so confrontational and having to force him to go rather than him just accept it and it's definitely exhausting having to have that battle in the mornings.
Violence is a whole other level and I don't think you can continue like this. I would speak to social services and the police unofficially and explore exactly what your options are and then present them to ds and say this is where we are heading if you continue to be violent.