Pass a dev server step once it says it listens

A quickstart that ends with flask run or litestar run never exits, so the step timed out and the run failed. A server command now gets a 90 s window, stops 2 s after its output says it listens, and passes. Python output is unbuffered, as in a developer's terminal. Flask went from 0 of 4 steps to verified 4 of 4, and Litestar from failed to 3 of 3.

Also takes the first Firecrawl key with credits from the key rotator, since slot 1 alone runs dry after a busy day.