It's not about you, though; it's about all of the fathers that will follow you. Does your partner see this dynamic as well? Will she support you by redirecting conversations to force your inclusion? That's where I would start, if you don't want to throw her under the bus with her admin.

Your point is correct of course and I have considered that. Where my partner stands is complicated because I share parents evenings with my ex, whose support I can not rely on to put it mildly.

She is teaching your daughter that treating you (or other men) this way is acceptable. I think it's worth the intervention for that reason.