Did I murder my yeast?

I pitched a pack of Safale 04 into my stout about a week ago. I forgot to take a temp reading and think the wort may have been over 80F when I pitched. (long day, long story:cross I had some air lock activity the next morning, and nothing since. I know that is not a good indicator, so last night I took a gravity reading and it is 1.019 at around 73F. There is no krausen, foam or anything on top, only the yeast looking exactly like they did when i sprinkled them into the wort. I did not hydrate them prior to pitching.
Could the high temp kill the yeast, or shock them so much they don't do their job?

I swirled the yeast around and got more air lock activity last night, but it has ceased as of this morning. I am going to give it a few more days, but was debating making a starter and dumping that into the batch, or pitching onto a fresh cake in 3-4 weeks.
Ideas?

What kind of beer is it? At 1.019, the beer may just be done. What was the OG?

+1 to it being done.You probably pitched to warm and sent the S-04 into overdrive.

S-04 has been known to ferment out in a 24 hour period. I would say it is probably done and just cleaning up after itself now. Give it another week and check the gravity.

Forgot to take the OG.
It is a stout loosly based on the tasty oats stout recepie on BMW site, but with a lot more oats, an additional pound of 2 row and a different hop selection and schedule.
Beer tools says it should be down around 1.013 so my plan is to wait a few days to see what happens and go from there I guess.
Even if it fermented out that quick, would the yeast still be floating on top with no krausen?

What you may be see are little floating yeast cakes it's fine. They will fall out of suspension eventually. I would also expect that you beer is probably done if only a few points off from the expected FG. Did you correct for temp?

Also, yeast die around 138* so you're probably okay.

Swirl it. If there is any work left to do, that will help get the yeast in suspension. Then let it sit another week.