Lots of really bad advice on this thread. Something to keep in mind is that people venting about how unfair this is and how you shouldn't give an inch as a matter of principle are writing that to gratify their own emotions more than they are honestly trying to help you in this situation.

You need to talk to a lawyer, strictly to figure out, given the structure of the company, what your partner has the authority to do. It sounds like they have an edge in ownership and are likely set up as the firm's CEO, in which case it's very likely that they can sever you from the company.

You can probably get a cost-effective answer to that question, especially if you're willing to accept the most straightforward answer (ie, if you're just using the lawyer as a sanity check, and not tasking them with pursuing weird theories of why you'd be impossible to fire). You probably cannot get cost-effective answers to the rest of your questions from a lawyer; be prepared to sink 5 figures into legal, speculatively, to pursue anything past that. On the firing, figure high hundreds of dollars. On the equity negotiation, figure $10,000.

At 11 months in to a 12 month cliff, you are going to get 0 if you're terminated. Maybe you can slow roll past the cliff?

Even if the paperwork is locked down on their side, your partner is likely going to offer you that 3% just to avoid the drama; your argument may be doomed legally, but you can easily inflict 5 figures of legal expense on them. So there's a negotiation here. It may be that as soon as you start to sound reasonable --- not asking to assume control of the company yourself, not expecting to walk away with all your shares vested --- they quickly become amenable to improvements in the deal, just to get this over with.

While you think this through, remember that it is also very early in the life of this company to have a departed founder with a huge equity stake. A lot of reasonable people in that situation would just wind down the company and restart it; why plow forward while encumbered the way they are now? You're (justifiably) thinking about the 11 months you just spent, but if the company has legs, those 11 months are not much compared to the person/years that are going to be invested down the road.

Nobody is going to raise money to liquidate your position in the company.

Nobody is going to court. Lawsuits that actually get litigated take years and cost more money than anybody in this story have.

It also doesn't seem realistic to expect investors at this stage of the company to buy out your partner. How would that even work? You'd end up working for the investor. Probably nobody wants that outcome, including the investor, but also: with the low revenue you're talking about, your investors are unlikely to waste their time.

I've been a party to some similar situations and my advice is just to keep things simple. A good mental model of the legal services you have available here is a complicated divorce: only the lawyers win, and they know it. Your time is worth a lot, and dragging this out will eat a lot of your productive time. You suggest downthread that you're not all that interested in the equity and think your partner is going to fly the company into terrain. I think you answered your own question with that. You can fight a little bit, especially if it makes you feel better, but it sounds like you'd be kind of crazy to fight a lot.