Here she also specifically mentions not having a partner rather than boy/girlfriend too. She's also quite neutral about most of the men she works with except the ones who make comments about how she needs a man or how she looks like she's on the prowl, both of which she clearly views with disdain.
This all goes past subtext even if she hasn't come right out and said "I want to date her" or something along those lines and even without having any actual input from the other lady that might suggest her sexuality. None of that actually disqualifies it from being yuri. The entire one-shot's premise is one woman's interest in another which is pretty explicitly implied to be more than a simple friendly interest. So very clearly yuri.
The fact that there's not like a billion OL yuri stories out there is criminal, honestly. It's two great tastes that go great together. Also gotta love a good happy ending. It ended just when it needed too, any more after that and it would've been anticlimatic.
And if you can't tell that this is yuri, how much more do you need to have it spelled out for you? It's not even subtext, it's very upfront about being a love story between two women. What more do you need, actual on-screen sex?