cap get_loose_ends todo output + add ack_todos_until bulk-clear (#2944)

hive-agent-sock/src/lib.rs

@@ -59,6 +59,10 @@ pub enum Request {
     },
     /// The agent marks one of its own todos done, by id.
     MarkTodoDone { id: i64 },
+    /// The agent bulk-acks every un-acked todo with `id <= up_to` in one
+    /// shot — the todo-store analogue of the message inbox's `ack_until`,
+    /// for clearing a backlog that piled up past the point of per-id triage.
+    MarkTodosDoneUntil { up_to: i64 },
     /// Schedule a reminder that fires into this agent's own turn loop at
     /// `timing` (harness-local — no broker round-trip). Same semantics as
     /// the old broker `Remind` request. `file_path`, when set, is where the