hivectl: add agent <name> watch to follow live events from the CLI

hivectl/src/agents.rs

@@ -1,6 +1,6 @@
 //! `hivectl agent <name>` — everything scoped to ONE managed agent:
 //! container lifecycle over the host admin socket (restart/pause/resume/
-//! spawn/kill/destroy/rebuild/set-parent/set-limits/choom), plus the
+//! spawn/kill/destroy/rebuild/set-parent/set-limits/choom/watch), plus the
 //! `quota` and `subvol` groups, whose handlers live in their own modules.
 //! `agents_list` (`hivectl list-agents`) is the one genuinely hive-wide
 //! read that lives in this module too since it shares the same daemon
@@ -210,6 +210,7 @@ pub(crate) async fn run_agent(socket: &Path, name: &str, cmd: AgentCmd) -> Resul
         AgentCmd::Choom { resume_session } => {
             crate::choom::choom(socket, name, resume_session.as_deref()).await
         }
+        AgentCmd::Watch => crate::watch::watch(socket, name).await,
         // `quota` and `subvol` keep their own modules — these arms are
         // just the reparenting glue that hoists `name` in from the
         // parent `agent <name>` command.