Child was told to tidy room, child didn't. Parent removed (in a black bin bag) all of child's belonging which were not put away properly...
My ideal would be that every person - adult or child - has a space of their own: a flat, a house, a room, a sectioned off area of a room, a cupboard, even. And what happens in that space is for them to decide. It is their fortress, their castle, their cave. If our children invited us in to their place to help tidy or rationalise old forgotten toys, we would help, but otherwise we would give them freedom in that place. That's my dream.
If your child wants her room tidy, she'll ask for help. And the baby? Well, when they arrive they'll want to be in with you to start with anyway, so it would be completely reasonable to put the baby clobber in one of your bits of the house until they are old enough to share a room, surely?
I believe that when parents try to impose their will on the rest of the family, to be the authority figures, to make other people change their behaviour and their personalities, to insist on their own standards of cleanliness and all sorts of other things, the family ends up in enormous conflict. The bin-bag removing your child's belongings is an example of that. What an awful situation for both you and your daughter.
Your daughter obviously isn't ready or willing to keep her room as tidy as you want it to be. So instead of punishing her for her preference, why not work with it? Just off the top of my head:
-If she has no objections, _you_ could clear the path to the wardrobe
-You could make it much easier to tidy - lots of those plastic storage crates maybe, so it's easy to run around throwing everything in a crate rather than putting on a shelf
-You could keep her clothes in the airing cupboard instead of fighting across the floor?
I'm a big fan of disciplining your surroundings rather than your children - making it so the conflict points just don't arise because of the way you've organised your surroundings. EG instead of trying to keep a cruising baby out of the kitchen cupboards, you fill everything in baby reach with things which are fine for the baby to play with