Is Violet Evergarden a robot, a cyborg or a human? So far, two episodes are out, and the following observations about Violet Evergarden are made:


She wants to learn what "I love you" means, a common trope among AI and other robotic characters.
She used to have human arms, but lost them during the Four-Year War.
In episode 2 when she was having dinner, we only saw her cut the fish awkwardly, but not eat or drink even once.
She's used to work long hours and her choice of word for eating and sleeping, "recharge", is not intended for humans.


So what is she, exactly?
She is human. This can be further proven by the fact that:


She can bleed. As seen during the flashbacks of the war from several episodes, namely one and two. If it was oil, it would've been black; which it wasn't. 
She has emotions. She was worried about Major Gilbert and was curious about the meaning of the phrase, 'I love you' and how it made her feel. 


She only looks like a robot because of her mechanical arms. She lost her human arms during the war. She is only awkward, because she never understood how to interact with other individuals in a normal society. She only knows how to act like a soldier.