add M-b hotkey to toggle manual unread bell on tmux windows

tmux/tmux-status/left.sh

@@ -69,6 +69,15 @@ fi
 
 get_session_icon() {
   local sid="$1"
+
+  # Check for manual @unread on any window in this session
+  local unread_win
+  unread_win=$(tmux list-windows -t "$sid" -F '#{@unread}' 2>/dev/null | grep -m1 '^1$' || true)
+  if [[ -n "$unread_win" ]]; then
+    printf '🔔'
+    return
+  fi
+
   [[ -z "$tracker_state" ]] && return
   local result
   result=$(echo "$tracker_state" | jq -r --arg sid "$sid" '