Tbh I think that yabu a bit, although I understand your thinking. When babies are little we get caught up in the excitement of what is and what will be and how life will be and who will get to do what and how and anyone who stands in the face of that is interfeering or trying to take away something that is yours by right...
And with the benefit of time you realise that a lot of this stuff really wasn't important in the scheme of things.
Firstly, are they actually demanding to have your baby once a week or is it a case that they had her once and now it's become a habit which you're finding it hard to say no to? Because in truth what you need to do is just to cancel one week, and then perhaps make it a lesser arrangement, once you've cancelled once you can perhaps start to re-arrange, especially now you're starting to enter the age of baby groups and such which may take up more of your time.
Toys at their house, perfectly normal, my mill had toys at her's for ds when we visited, it made visiting exciting because granny may have bought something, and there was a cupboard with all of them in etc. Bedroom with her name on it, well no-one has said she's moving in, perhaps they envisage she and even you might stay overnight some time, but if you don't you don't, and in time there will be other grandchildren and the novelty of that will wear off.
Hand and foot prints and locks of hair... well, Christmas presents sorted then. pictures, ... my mum had professional pictures taken of mine and my sister's kids when they were little. I don't have copies of them. it's normal for people who spend time with your child to want to take and have pictures of them, especially when that's a grandchild.
And a stocking as well as presents... again, it's their choice and there really is no harm. And in truth, no-one owns a tradition. Your dd will grow up knowing that they get a stocking at home first thing and that they get stockings and presents at granny's too. Where's the harm.
As long as this really is coming from a place of kindness and excitement there really is no harm in any of it.
PS: my pfb is now thirteen, and when I look back at the things which irationally upset me when he was little I cringe at some of it.
my ds now has a great relationship with all of his grandparents, and as long as people are well meaning and not generally abusive then most of this stuff really isn't that important.