Turns out, that's what Lucia is. I sent in her DNA to a research company (Embark) to see if she had any breeds that stand out.
The results confirmed what I assumed, but wasn't 100% sure about. She was adopted as a puppy while I was in Vladivostok, so I knew her heritage would be mostly a mix of breeds. But I guessed she had traits of German shepherd and some kind of terrier. Embark's results verified what I was thinking. You can see all their details here.