I don’t think that’s entirely fair.
Yes, obviously the colleague is communicating with the OP in that all behaviour is communication, but I don’t see the OP as being in any way unreasonable to want to understand the terms of the ‘relationship’ (to the extent that it is one) better, rather than just being the passive recipient of the other woman’s occasional company, and obliged to react passively to whether the colleague feels like talking or not, without herself being able to express a desire of her own.
It may be, of course, that this is simply not a situation that will ever develop into a friendship, as it’s too one-sided.
OP, judging by Mn, most people misuse the term ‘introvert’, when what they actually mean is ‘socially-awkward’, ‘shy’, or ‘socially anxious’, or, in some cases ‘misanthropic’.
I am an introvert — a sociable one. I love company, friendships and meeting interesting new people, but I need vast amounts of time alone to compensate. You would not ‘know’ in company or at work, unless I was exhausted and had had no recharge time. It might be that I would need lunch alone at times, depending on the job, but if I genuinely liked a colleague, I would communicate with them explicitly about that, not just expect them to second-guess me on a specific day, or to accept that my needs as an introvert should be prioritised over theirs. Friendship is a two-way thing.
Its not possible to tell from your post, OP, whether this woman is socially-inept, shy, an introvert who is exhausted by the demands of the job, or simply has no idea how her behaviour impacts on others. But if you want your needs to be met, too, this might not be for you.