feat(cli): add PJ_STATE env handling for task state communication

dot_local/bin/executable_pj

@@ -16,6 +16,10 @@
 # Env:
 #   PJ_QUIET=1   suppress the "no task sources" error — the down-arrow
 #                bindings use this, where an empty tree is the normal case.
+#   PJ_STATE=FILE  key bindings pass a path; pj writes `open` to it when the
+#                  picker opens and `pj --run` writes `ran`, so the binding
+#                  can tell "no tasks" / "cancelled" / "task printed output"
+#                  apart and redraw the prompt accordingly (tv --inline).
 #
 # Cable entry points (tab-separated record fields, see `--list`):
 #   pj --list                          print one record per task
@@ -150,6 +154,8 @@ fi
 if [ "${1-}" = --run ]; then
     kind=${2-} target=${3-} root=${4-} runner=${5-}
     cd "$root" || exit 1
+    # Tell the key binding a task ran (its output now sits below the prompt).
+    [ -n "${PJ_STATE-}" ] && echo ran >"$PJ_STATE"
 
     # Extra args from `pj a b …`, shell-quoted into $PJ_EXTRA by the picker.
     extra=()
@@ -440,4 +446,5 @@ if [ $# -gt 0 ]; then
     PJ_EXTRA=$(printf '%q ' "$@")
     export PJ_EXTRA
 fi
-tv pj --source-command "cat '$tmp'" --input-header "$primary"
+[ -n "${PJ_STATE-}" ] && echo open >"$PJ_STATE"
+tv pj --inline --source-command "cat '$tmp'" --input-header "$primary"