By your account, there haven't been breadcrumbs for months, and now it's cupcakes, vaccine info, and a lunch date. Is this meaningful? Probably. Is she remorseful and ready to reconcile? Probably not.
You have to act in accordance with where your head and heart are. Consider you've stood so long while she's out-of-contact and exploring OM. I would take action to move forward or move on if you can without regrets. In a way this is a meaningful moment--she's more vulnerable than usual if she's suddenly breadcrumbing you. You have three exit plans to consider: a. Filing D, b. One last discussion, c. Discernment therapy.
If you're NOT ready to move on, that's okay, just do some self-work to figure out why so this doesn't go on forever. Some get stuck. I don't think you will. There are at least four reasonable ways to respond outlined in your thread. There are also bad ways, e.g. respond positively to the breadcrumbs ("I'm still a backup. It's OK to explore OM") or make empty threats ("I'm a backup.. and out-of-control! It's wise to explore OM.")
