fix(hooks): stay silent on events that need no attention

Only turn end and the moments needing the user should signal. Any other
event reaching the hook, such as agent_completed or auth_success, now
exits without emitting, so a subagent finishing rings nothing even if the
Notification matcher is ignored.

hooks/notify-attention.sh

@@ -33,7 +33,9 @@ case "$event" in
   agent_needs_input) label="Asks you a question" ;;
   idle_prompt) label="Waiting for you" ;;
   elicitation_dialog|elicitation_url_dialog) label="Needs your input" ;;
-  *) label="Needs your attention" ;;
+  # anything else (agent_completed, auth_success, quota_*) stays silent:
+  # signal only for turn end and moments needing the user.
+  *) exit 0 ;;
 esac
 
 detail=$(read_field '.message')