Respond To Permission Requests Batch

Resolve a whole approval SET in one round trip.

A turn that raises several approvals used to cost the client N sequential round trips, each racing the others' expiry windows. This resolves them together -- but ONLY as a transport convenience: every decision is authorized individually through _resolve_permission_response, the same function the single endpoint uses, so a set cannot be used to answer a request the caller could not have answered on its own.

One bad item never fails the batch: each result reports its own outcome, so a client can show "2 sent, 1 already expired" instead of retrying everything.