Not at all, it's too obvious they were going for yuri bait this time. The fact is they structured Ruri's "confession" moment so much like a love confession, having them both blush and look away from each other afterwards too, it felt pretty off.
In fact, everything was playing out pretty naturally until that very scene. It's specially strange, since Ruri is likely 15 or 16 and Nagi is about 24 years old. (this probably means it's just bait and that this kind of development is going to get dropped soon, unless we're looking at a somewhat shocking story. Actually, I wonder if the author will rather just play it as an innocent crush that doesn't get acted on?)
You don't need to be a shipper to notice how the story is deliberately applying some very typical romance tropes. Otherwise, that moment should have played out very differently.
Blushing, shyness and good chemistry so on isn't exclusively romantic tropes. People, especially young girls doesn't feel shy only in romantic moments. And of course, love confession isn't only way, when people told others that they're important for them. Especially when we talk about cute girls fiction, not realistic real live setting. You just bring things, that can be read differently without context and argue, that only romantic POV could be the only one possible. While when something in the chapter or arc directly contradict this even for you, you just ignore this with "this is strange" remark.
So, no, this is a archetypal moment in all female moe manga, when author show that bond between girls become so deep and strong, that no one can separate them now. Of course, no one is stopping you from interpreting it differently, and you have every right to do so, but that shouldn't become dogma, especially when there is a clear logical context for it. I don't know how things will develop from here, as far as I understand, only half the available manga has been translated. But right now, this whole mess doesn't even qualify as bait (and of course, not all unsuccessful yuri expectations are deliberate bait, sometimes it's just cope). It’s essentially just an attempt to make things sound ambiguous by deliberately seeking out strictly romantic interpretations and descriptions of the girls' bonding moments. Atleast for now.