Just say no. No screaming allowed. Say it calmly and tell her you're going back home if she keeps it up. And go.
My dcs never screamed after I got down on the floor in tesco beside them and screamed with them. They were so shocked and they then knew they couldn't manipulate me with noise.
Screaming isn't anything to be afraid of- she's using your fear of creating a scene to manipulate you to do what she wants.
You need to learn how to negotiate with her. Teach her sign language? We found that vey helpful before they were pre verbal.
Keep her hydrated
and show her pictures of outdoor items.
Coat, hat, shoes, gloves.
Then a picture of outside.
Then pictures of inside, with no hat no coat no shoes no gloves.
Comment on how everyone wears shoes outside.
Also I think she's too young to wear shoes, so get her something to distract her when she's in the buggy, like a little cardboard book attached to the buggy.
Remember be calm and be compassionate, and show her shoes on everyone. Point them out.
Go to a shoe shop to see other children getting shoes fitted. Let her watch. Don't get her fitted until she's at least 15 months.
If she really doesn't want to wear any kind of shoes, get her swimming socks- they're waterproof. Put them on over a nice thick pair of socks.
Don't fight with her, stay calm and follow up on any "threats".