Who called up the corner hounds and why didn't anyone notice...?

[Conspiracy Theorist]

Using all his power at its most intense at the closest of ranges from the most powerful of wizards.

[vultur]

I think it is important that Harry to Butters called then the Hounds of Tindalos its from there the time travel connection was made

Well, the first lines of Chapter 13 are

Hounds of Tindalos are real, huh?" Butters asked. "Weird."
"Well. For some values of 'real'," I said. "Lovecraft got kicked out of the Venatori Umbrorum for mucking about with Thule Society research.

"For some values of 'real'" might mean that the story description of them is not quite accurate, so I don't know that we can necessarily say that the Hounds work that way in the Dresdenverse. (It does seem that the "enzyme" thing they had in the original story has been replaced by an infrasound attack.)

BTW, Hounds of Tindalos aren't actually from Lovecraft... they are a Frank Belknap Long invention.

[Mira]

   Just a thought, but Justine might have called them up.  It isn't out of the question that with her association with the Raith family and those around them that she'd be aware of words and ritual to call them up.  Funny this happens shortly after Harry pays her a visit, don't you think?