this is why we're calling for developer-level opt outs, among other things. Not just per-user consent/opt-in.

No worries! This means that we, at Signal--the ones developing the app--should be able to opt-out as Signal. To say, "no data access for you, Agentic AI." Instead of leaving that to each person who uses Signal (which invites the issues you rightly name--the fact that one person ultimately makes that choice for more than themselves, in a way that could still compromise their interlocutors' privacy).