Alright. That’s bullshit. Not entirely. But it’s riddled with it. The “k” part, I understand. This can be considered rude and to be honest, it’s my way of saying “whatever dude”.
BUT that’s how I use it. I have met people who use it as a lazy but friendly way of “alright, got it”. So it depends on who uses it and what its intention is supposed to be. You either have to be incredibly nuanced or have to know the person who is using it to properly interpret it. Which your friend kinda doesn’t. I’m not blaming her. I fail at it way too often myself.
The “ending a sentence with a period” on the other hand? My answer would have been “Are you high?!” Seriously, it doesn’t make any sense and it sounds made up.
Edit: Thinking about this makes me even angry ffs.