You didn't ruin the beer! It's just that, uncooked, the rice wouldn't have converted and so may give you a bit of a starch haze and not brought anything to the beer.
As far as the SF lager yeast, it's a hybrid strain. You can definitely lager after fermentation if you want to, and I think it makes a crisper finish. You may especially want to lager if you have a starch haze, because lagering will help clear the beer.
You will want to hold at your fermentation temperature for at least 7-10 days, or at least for 3 days after the beer reaches FG. Also, that strain can produce diacetyl so you may want to consider raising the temperature at the tail end of primary (now) to encourage the yeast to clean up any diacetyl. After that, you can rack and lager if you'd like.
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